Sean Lannon pleaded guilty to five killings committed in early 2021, four in New Mexico and one in New Jersey. The victims in New Mexico were his former wife, Jennifer Lannon, 39; two of her friends from Grants, Jesten Mata, 40, and Matthew Miller, 21; and Randal Apostalon, 60, an Albuquerque man who gave people rides for money. Their bodies were found together in a parked pickup truck in Albuquerque on March 5, 2021. By then Lannon had flown to New Jersey. Three days later Michael Dabkowski, 66, who had mentored Lannon and his twin brother through a Big Brothers program in the 1980s, was found dead in East Greenwich Township, south of Philadelphia.
Lannon was arrested on March 10 in St. Louis, driving Dabkowski's car. At a detention hearing in New Jersey, a prosecutor said he had claimed to have killed the four people found in Albuquerque and 11 others in New Mexico. Police in New Mexico found no sign of any further victim. In New Jersey he pleaded guilty in October 2022 to first-degree murder and received 35 years. In New Mexico he pleaded guilty in 2024 to four counts of second-degree murder and received 60 years.
Little about Lannon's early life is in the public record. At his first detention hearing in March 2021, his New Jersey public defender, Frank Unger, told the court that Lannon was born in Massachusetts, spent most of his early years in Gloucester County, New Jersey, in the suburbs of Philadelphia, and later served in the Army, including a deployment to Germany. Unger said Lannon had no prior convictions and had been honorably discharged. Lannon has a twin brother; in the 1980s, according to NJ.com reporting relayed by the Associated Press, Michael Dabkowski mentored both boys through Big Brothers. His family, including his mother and sister, lived in southern New Jersey.
Detectives in New Jersey, in charging documents described by WPVI-TV in Philadelphia, called him a former member of the military with a history of drug abuse and a record of violence. At the March 2021 detention hearing, Assistant Prosecutor Alec Gutierrez noted that Lannon had once spent a week in jail in New Mexico for failing to appear in court; the reports do not say what the original matter was.
Sean and Jennifer Lannon were married for nearly a decade, according to her brother. They lived in southern New Jersey, where property records show several addresses for him before 2020. In 2015 the couple filed for bankruptcy in New Jersey, listing about $14,000 in personal property and more than $550,000 in liabilities, including $83,000 in student loans, against a combined monthly income of about $13,000.
A few years before 2021 the family moved to Grants, a small city in Cibola County, about 80 miles west of Albuquerque. Sean Lannon filed for divorce, and court records show the couple divorced in 2019. That year he was awarded sole custody of their three children. A protective plan drawn up by New Mexico's Children, Youth and Families Department allowed Jennifer Lannon only supervised visits, because of concerns about neglect linked to prescription drug abuse. Her brother told the Associated Press that the two were still living together after the divorce, were still parenting together, had talked about moving back East, and showed no sign of trouble.
Jennifer Lannon was 39. She was a mother of five, and she had lost custody of her children because of her struggle with prescription drugs. On social media she wrote about resilience and about understanding herself better after a hard stretch, and she described the previous summer as a quiet, happy one spent on small moments with her family. Shortly before she disappeared she posted a birthday message to her daughter, who was turning six: "Somehow you were able to learn early on that life is too short to take it for granted." Her family remembered her as a loved daughter, sister, friend and mother. "She was a great mom," her brother said, "and, just, it would be uncharacteristic of her to not be with her children."
Jesten Mata was 40. He grew up in Show Low, Arizona, where his family still lived. He had struggled with substance abuse and had been jailed on charges ranging from shoplifting to drug trafficking, and his record made it hard to find work in Grants, his fiancée said. He had a teenage son from an earlier relationship and had talked about changing his life for his children and for his fiancée's children. Her five-year-old son considered him his best friend. "He was a real nice person," she told the Associated Press. "He would help anybody." A former girlfriend who had known him since high school said they had talked the year before about his getting to know his son and getting his life on track.
Matthew Miller was 21. His father had died in January 2020, and his mother and grandparents died in the months that followed; an aunt told KOB-TV that he had lost his mother, father and two grandparents within a year. He had battled a brain tumor, his aunt said, and his grandmother told the Associated Press that a health problem with his brain kept him from working, so that he sometimes could not pay his utilities and came to her house to fill buckets with water or to shower. He had an addiction to opioids and minor brushes with police over things like loud music and traffic violations. Lt. David Chavez of the Grants police said Miller "had his demons," but described him as a decent young man who was fond of his pets. He would never have left his dogs and cats, the police said, and that was one reason they knew something was wrong. His aunt said he used to come over for her children's birthday parties. "He wasn't a bad kid," she said. "He's been through so much in his life." His grandmother said he "didn't deserve this."
Randal Apostalon was 60 and lived in Albuquerque. After financial trouble he had been working odd jobs, and he lived out of his vehicle and gave people rides for money. He had no criminal record. Albuquerque police said he was likely in the wrong place at the wrong time.
Michael Dabkowski was 66 and lived in East Greenwich Township, Gloucester County, New Jersey. He had been a Big Brothers mentor to Lannon and his twin brother in the 1980s. Jennifer Lannon's brother told the Associated Press that he had met Dabkowski a couple of years before at a birthday party for one of the Lannon children; everything had seemed fine, and Dabkowski had seemed to be a close friend of Sean's and a father figure to him.
What happened inside the Lannon house in Grants is known mainly from Lannon's own statements to investigators. They were never tested at a trial, because the New Mexico charges ended in guilty pleas.
At his detention hearing in New Jersey in March 2021, Assistant Prosecutor Alec Gutierrez said Lannon had confessed to luring several victims to a home in New Mexico and had admitted his efforts to conceal evidence. Lt. Chavez of the Grants police said Lannon had claimed he shot his wife and her boyfriend, and added: "Matthew was not her boyfriend, so I don't know how he became involved." The Albuquerque Journal, describing what Lannon told police, said he killed his wife after catching her with Mata, then lured Mata and Miller to the house days later and killed both men, all in January. Court documents described by the Cibola Citizen put the three killings in mid-January 2021, over about a week. Police, in Associated Press reports, said the three had been lured to their deaths over several weeks; the two time spans have never been reconciled.
He told Jennifer Lannon's family in January that she had run off with friends, possibly to Arizona. "It didn't sound right," her brother said later. When the family could not reach her, they filed a missing person report.
According to court documents described by the Cibola Citizen, the bodies of all three were hidden in plastic containers and tote bags. He later took the containers to Albuquerque.
The first sign of trouble was Miller's absence. Late in January 2021 he was reported missing; the Associated Press quoted Lt. Chavez as saying that Miller's girlfriend made the report, while KOB-TV reported that Grants police said it was his grandmother. Detectives then learned that others in Grants might also be missing. Police wanted to question Jennifer Lannon and Jesten Mata about Miller, and found that they too had disappeared. Chavez said investigators were trying to learn whether the two knew where Miller was, and that they had not been in contact with anyone.
For a time the Grants police looked elsewhere. In February 2021 the department posted on Facebook that it was seeking a different suspect in the three disappearances. When the bodies were identified in March, Grants police named a relative of Miller's as a person of interest who, they said, had information for them. The charges that followed were brought against Lannon.
In Albuquerque, according to court documents described by the Cibola Citizen, Lannon asked people whether he could use their storage space. Randal Apostalon offered his storage unit, which turned out to be too full, and the two men looked for another place. Albuquerque police said Apostalon died of blunt force trauma. The Cibola Citizen, citing court records, put his death on February 24, 2021. Lannon told police, according to the Albuquerque Journal, that he killed Apostalon after Apostalon refused to help him move the bins. A 2023 Cibola Citizen report said Apostalon had hinted that he knew what was in them. The New Jersey AP accounts summed up what the authorities said: Apostalon had agreed to help move the bins without knowing what they held.
The Cibola Citizen's account of the next days, drawn from court records, is that Albuquerque police, carrying out a welfare check that the Children, Youth and Families Department had requested, found a warrant for Lannon from Cibola County. He was taken to the Cibola County Correctional Center in Milan and was released on March 2. He then returned to Albuquerque, left the vehicle, and flew to New Jersey.
Relatives said he flew to New Jersey on March 4 with the couple's three children, then aged 4, 6 and 7. He left them at his parents' home and said he was going back to New Mexico to keep looking for Jennifer.
On March 5, 2021, Albuquerque police were called about a foul odor from a parked vehicle in the city. Inside were four bodies. The vehicle was Apostalon's own pickup. Within two days police had identified the four as Matthew Miller, Jennifer Lannon, Jesten Mata and Randal Apostalon, and the Albuquerque Police Department began working with the Grants police on the connection to the three people missing from Grants since January. Gilbert Gallegos Jr., a spokesman for Albuquerque police, said one victim appeared to have been killed in Albuquerque and the other three in the Grants area.
At first Lannon was described only as a person of interest. Miller's aunt told KOB-TV that the family was waiting for anyone to come forward with information. "Anything helps," she said. "Just to get justice."
On March 8, officers carrying out a well-being check found Michael Dabkowski dead in East Greenwich Township. The Gloucester County Prosecutor's Office said he died of blunt force trauma. Prosecutors said Lannon had broken into the house and beaten him to death. Lannon was also accused of forcing his way into a home in nearby Elk Township while armed with a knife, and he was charged there with burglary and a weapons count.
After the killing, according to the charging documents, investigators received a call from a witness the documents called credible, who said Lannon had admitted the killings in New Mexico and then the killing of Dabkowski. Court documents in the New Mexico case later said he had admitted the killings in a phone call to a relative, who told investigators he sounded remorseful.
Lannon took Dabkowski's wallet, keys and car, a blue 2018 Honda CR-V. Before his arrest, the Gloucester County prosecutor's office said he might have been seen in Camden on the afternoon of the killing and called him armed and dangerous. The U.S. Marshals Service offered a $5,000 reward for information leading to his arrest.
Lannon was arrested at about 7:30 on the morning of March 10, 2021, in the Lindenwood Park area of St. Louis. The U.S. Marshals Service announced the arrest; a neighbor told KSDK-TV that she looked out to see about a dozen men go past her door. The Cibola Citizen later reported that a St. Louis police officer running license plates found the car listed in the National Crime Information Center and made the stop. The Albuquerque Journal said he was found asleep in the car, apparently on his way back to New Mexico. Officials said they did not know why he was in Missouri.
A federal judge in St. Louis signed a warrant for his transfer to New Jersey. That afternoon Gloucester County charged him with murder, robbery, burglary, theft of a motor vehicle and weapons offenses in Dabkowski's death. The acting Gloucester County prosecutor, Christine Hoffman, said further charges were coming. Albuquerque detectives flew to St. Louis to interview him, and Grants police spoke with him soon after the arrest. The FBI joined the investigation because the case crossed state lines.
At Lannon's detention hearing in Gloucester County in March 2021, reported on March 21, Assistant Prosecutor Alec Gutierrez told the judge that Lannon had confessed to luring several victims to a house in New Mexico and to trying to hide evidence, and that he had claimed to have killed the four people found in Albuquerque and "11 other individuals" in New Mexico. With Dabkowski, that made 16 killings by his own count.
A law enforcement official told the Associated Press that investigators were checking missing person records, police reports, electronic and financial records and surveillance video. Lt. Chavez said Grants police had no reports of missing people or homicides that matched. "Is it possible? Sure, anything's possible," he said. "Is it plausible?" He later called the claim possible but not probable. Cibola County investigators, the Cibola Citizen reported in 2023, found no evidence that Lannon had killed anyone else in the county. No further killing has been charged against him, and the claim stands only as his own unproven statement.
At the same hearing Unger challenged the probable cause for the murder charge. He said Dabkowski had let Lannon into the house and argued that the death was at worst passion-provoked manslaughter, that Lannon had brought no weapon, and that Dabkowski had attacked first. Lannon told investigators that he had gone to the house because of wrongs he said Dabkowski had done him in childhood, an accusation that, as the Associated Press reported at sentencing, was never supported by any evidence presented in court. The judge ordered Lannon held. Jennifer Lannon's brother told the Associated Press that the family had known nothing of such an accusation. He said the family was angry and hurt, that part of him felt sorry for Lannon, and that "we still want justice."
On March 26, 2021, the Associated Press reported that Lannon had been charged in New Mexico with murder in the deaths of Jennifer Lannon, Jesten Mata and Matthew Miller. The Cibola Citizen later listed the Cibola County counts as three of first-degree murder (willful and deliberate) and five of tampering with evidence, and the Bernalillo County counts, for Apostalon, as one of first-degree murder and one of tampering with evidence. At the end of March no charge had yet been filed for Apostalon's death.
The New Jersey case was resolved first. In October 2022 Lannon pleaded guilty in Gloucester County to first-degree murder in Dabkowski's death. He was sentenced in Gloucester County Superior Court to 35 years in New Jersey State Prison; the sentencing was reported on December 22, 2022. A representative of the prosecutor's office told Patch that he would be eligible for parole after serving 30 years, and the Cibola Citizen reported in 2023 that his parole eligibility date in New Jersey is March 10, 2051. Reporting on the sentencing noted again that no evidence had ever been presented in court to support his accusation against Dabkowski.
At that point he still faced the four murder charges in New Mexico, and two New Mexico district attorneys' offices said they intended to bring him back to face them.
On January 10, 2023, the court of Cibola County Magistrate Judge Tony Mace issued a warrant for his extradition. A New Jersey Department of Corrections spokesperson said that month that he was in a COVID-19 quarantine at the Garden State Youth Correctional Facility. The magistrate case was dismissed so that a higher court could take it, and the 13th Judicial District Court picked it up.
Hearings in the Cibola County case kept stalling. Lannon was to be arraigned by video link on April 7, 2023, but was not connected, because the time difference between New Mexico and New Jersey had not been allowed for. On May 1 he again did not appear; defense lawyers said officials in New Jersey had not been communicative. On June 5 he missed a third video hearing, and District Judge Amanda Sanchez Villalobos ordered that the next one, set for July 24, be held in person. The court let the Albuquerque case go ahead with the extradition paperwork, since that court was already bringing him back.
On June 15, 2023, Lannon was returned to New Mexico to face Judge Brent Loveless of the Second Judicial District Court in Albuquerque on the charge in Apostalon's death. At his arraignment in Albuquerque, reported by KOB-TV, his lawyer, Chandler Blair, waived a formal reading of the charge and said that Lannon would "stand silent as to a plea." Judge Cindy Leos entered a plea of not guilty on his behalf. He was held at the Metropolitan Detention Center in Albuquerque.
In May 2024 the Albuquerque Journal reported that Lannon, then 50, had agreed to plead guilty to second-degree murder in all four New Mexico deaths. Under the plea agreement, filed in the Second Judicial District Court, he would serve 15 years for each killing, 60 years in all, in the New Mexico Corrections Department. The original New Mexico charges had been first-degree murder; the pleas were to second-degree murder.
KRQE News 13 reported the sentences in two stages. Lannon first admitted killing Apostalon and was sentenced to 15 years for that killing. Then, on June 5, 2024, he pleaded guilty to three counts of second-degree murder for the deaths of Jennifer Lannon, Jesten Mata and Matthew Miller, and received 45 years, to run consecutively to the 15-year term for Apostalon. That made 60 years in New Mexico, matching the plea agreement the Journal described.
Reports disagree on how the New Jersey and New Mexico sentences relate. The Albuquerque Journal, describing the plea agreement, said that Lannon would return to New Jersey to serve his 35-year sentence there first and would then come back to New Mexico to serve the 60 years. KRQE reported in June 2024 that the New Jersey sentence runs concurrently with the New Mexico sentences. Neither report quotes the judgment itself.
As of June 2024, Lannon had been sentenced in both states and was in custody. The Albuquerque Journal reported in May 2024 that he was being held at the Metropolitan Detention Center in Albuquerque. Under the New Jersey sentence he is eligible for parole there in 2051, according to the Cibola Citizen.
An online fundraiser for Jennifer Lannon's family raised more than $21,000, Patch reported. Matthew Miller's family raised money for his funeral, and his grandmother said she planned to have him cremated and his ashes placed beside his mother's.
Lannon had told his former wife's family that she had run off with friends. Jennifer Lannon's family said that story never fit the woman they knew. Lt. Chavez said drugs were not the main motive in the killings and called the case complicated, with many separate parts.
The 11 further killings. Lannon claimed, in a call to a relative and to investigators, to have killed 11 people in New Mexico besides the four found in Albuquerque, which with Dabkowski would make 16. Police in Grants and investigators in Cibola County found no missing person reports, homicide reports or other evidence to support the claim, and no further charge has been brought. It is his claim only.
His account of the Grants killings. The sequence and the reasons he gave come from his own statements to investigators. They were never tested at trial.
His accusation against Michael Dabkowski. Lannon said Dabkowski had wronged him in childhood and that this was why he went to the house. The Associated Press reported that no evidence was ever presented in court to support the claim, and he pleaded guilty to first-degree murder.
Who reported Miller missing. The Associated Press quoted Grants police as saying his girlfriend reported him missing; KOB-TV reported that police said his grandmother did.
How Apostalon came to be killed. Reports differ on what Lannon said: that Apostalon refused to help move the bins (Albuquerque Journal, 2024), or that he hinted he knew what the bins held (Cibola Citizen, 2023).
Who stopped him in St. Louis. Reports at the time credited the U.S. Marshals Service; the Cibola Citizen later said a St. Louis police officer found the car through a license-plate check.
The sentences. Whether the New Jersey term runs before or alongside the New Mexico terms is reported both ways.
1980s: Michael Dabkowski mentors Lannon and his twin brother through Big Brothers.
2015: The Lannons file for bankruptcy in New Jersey.
2019: The couple divorce; Sean Lannon is awarded sole custody of their three children.
January 2021: Jennifer Lannon, Jesten Mata and Matthew Miller are killed in Grants; court documents put the killings in mid-January, over about a week. Lannon tells her family she has run off with friends.
Late January 2021: Matthew Miller is reported missing in Grants; police find that Jennifer Lannon and Jesten Mata are missing too.
February 2021: Grants police say on Facebook that they are seeking a different suspect.
February 24, 2021: Randal Apostalon is killed in Albuquerque, according to court records described by the Cibola Citizen.
March 2, 2021: Lannon is released from the Cibola County Correctional Center after being held on a county warrant.
March 4, 2021: He flies to New Jersey with his three children and leaves them with his parents.
March 5, 2021: Albuquerque police find four bodies in a parked vehicle in the city.
March 8, 2021: Michael Dabkowski is found dead in East Greenwich Township, New Jersey.
March 10, 2021: Lannon is arrested in St. Louis in Dabkowski's car and charged in New Jersey with murder and other offenses.
March 2021: At a detention hearing in Gloucester County, a prosecutor says Lannon claims 16 killings in all; he is ordered held.
March 26, 2021: Reports say Lannon has been charged in New Mexico in the deaths of Jennifer Lannon, Mata and Miller.
October 2022: Lannon pleads guilty to first-degree murder of Michael Dabkowski.
December 2022: Sentenced to 35 years in New Jersey State Prison (reported December 22).
January 10, 2023: Extradition warrant issued in Cibola County.
April to June 2023: Three Cibola County hearings fail because Lannon is not connected by video from New Jersey.
June 15, 2023: Lannon is returned to New Mexico.
2023: Arraigned in Albuquerque on the Apostalon charge; a plea of not guilty is entered for him.
May 2024: Plea agreement to four counts of second-degree murder, 15 years each, reported by the Albuquerque Journal.
2024, before June 5: Sentenced to 15 years for Apostalon (KRQE).
June 5, 2024: Pleads guilty to three counts of second-degree murder for the Grants killings; 45 years, consecutive to the Apostalon term, 60 years in New Mexico in all.