On the morning of September 22, 2021, the remains of one man and two women were found in Fort Worth. Days later detectives arrested Jason Alan Thornburg, a 41-year-old electrician's apprentice who was living in a motel in Euless, in the same county. According to the arrest warrant, he told them he knew the Bible well and believed he was being called to commit sacrifices.
The three were David Lueras, 42, Maricruz Mathis, 33, and Lauren Phillips, 34. In November 2024 a Tarrant County jury rejected Thornburg's insanity defense and convicted him of capital murder, and on December 4, 2024, it sentenced him to death. Police said he had also confessed to two earlier killings: that of his roommate, Mark Jewell, who died in May 2021 when their Fort Worth house filled with gas and exploded, and that of his former girlfriend, Tanya Begay, who disappeared in 2017 during a trip with him in Arizona. He was indicted for murder and arson in Jewell's death; that case has not been tried. Tanya Begay has never been found. His direct appeal was argued before the Texas Court of Criminal Appeals in October 2026.
Jason Thornburg was born on August 27, 1980, according to the Texas Department of Criminal Justice. Little is known of his early life beyond what came out at his trial. His uncle, the final defense witness in the punishment phase, described a difficult childhood on a Navajo reservation and told the jury that Thornburg's mother had used drugs while she was pregnant with him, NBC 5 Dallas-Fort Worth reported. Defense experts testified that he had partial fetal alcohol syndrome and had suffered other trauma as a child.
As an adult he worked as an electrician. At trial an attorney noted his long work history in the trade and a 4.0 grade point average at a community college, facts the prosecution used to argue that his thinking was organized, according to FOX 4. At the time of his arrest he was an electrician's apprentice.
His record before 2021 is reported unevenly. A Fort Worth police sergeant told reporters after the arrest that he had no extensive criminal or violent history. 12 News in Phoenix reported that he had been convicted in a 2015 vehicle theft case and paroled in February 2016, and it mentioned a 2014 carjacking case in Pima County, Arizona, without saying how that case ended.
Religion ran through what he later told police. An affidavit quoted by CBS Texas said he had attended a leadership conference taught by one of the people he was later accused of killing, and that on a worksheet there he wrote that he wanted to be a missionary and that his greatest strength was "a sense of purpose, a sense of destiny that must be achieved." Residents of the Euless motel told CBS Texas that he regularly handed out fliers for a local church and read the Bible outside his room.
Tanya Begay was 36 in 2017, a Navajo woman from Gallup, New Mexico, and the mother of two children. A friend who had known her since 2014, when they met in Phoenix, told 12 News that she was "an amazing woman and loved her kids." By early 2017 she and Thornburg were in a relationship. Her mother later told police it was an abusive one, according to 12 News.
On February 18, 2017, Gallup police answered a domestic disturbance call and found Tanya Begay injured. She told them Thornburg had assaulted her. New Mexico assault charges against him were dropped on June 22, 2017; 12 News reported that they were dropped because she did not take part in the case.
Her mother told Gallup police that Tanya was last seen on March 2, 2017, leaving the home of relatives in Tohatchi, New Mexico, with Thornburg. The next day Tanya called to say she was with him in Leupp, Arizona, on the Navajo Nation. In another account, published by the Associated Press, she last told her mother she was driving from Leupp across the Navajo Nation toward Gallup. Gallup Police Chief Erin Toadlena-Pablo said her phone connected to towers in Tohatchi and in Dilkon, Arizona. "Tanya Begay was last seen in Tohatchi, New Mexico," the chief said.
Her mother first tried to report her missing to the Navajo Nation police in Crownpoint, New Mexico, she later said, but no report was filed there. On March 19, 2017, she reported her daughter missing to the Gallup Police Department. Missing-person posters said the car the couple had been driving was later found abandoned, CBS Texas reported. Thornburg was arrested in Gallup on March 21, 2017, but police did not treat him as a suspect in her disappearance, and the interview ended when he asked for a lawyer, according to 12 News. He told the owner of the apartment he rented that he and Tanya had argued and that she had left him in Holbrook, Arizona.
Gallup police continued to list her as missing and passed what they had to the Navajo Nation police and the FBI. In September 2021 a spokesperson said the Navajo Nation police were the lead agency on her case.
By 2021 Thornburg was living in Fort Worth with a roommate, Mark Jewell, who was 61. On May 21, 2021, minutes after Thornburg left for work, the house filled with gas and exploded, and Jewell was found dead. The medical examiner's office could not determine a cause of death because of the explosion, WFAA reported. Thornburg spoke at Jewell's funeral, CBS Texas reported.
Fort Worth police investigated the death as suspicious, and Thornburg was a person of interest in it, the Associated Press and WFAA reported.
In late July 2021 Thornburg moved into a motel in Euless, one of the cities between Dallas and Fort Worth, according to his arrest affidavit as reported by the Associated Press. Police said he knew the people he killed there, two of them only casually, and that he met them at the motel.
David Lueras was 42. He came to Thornburg's room about five days before the remains were found, according to the affidavit, and shared it with him. Thornburg told police he killed him there. Lueras's mother said after the sentencing that the victims "have been home with Jesus since their last breaths." His sister told the court that the defense's opening words about the value of life applied to her brother too, and that the trial had been agony for the family.
Maricruz Mathis, also named in some reports as Maricruz Reyes-Mathis, was 33. Her parents adopted her when she was 9. She was the mother of a young son, she loved church and had taken part in youth programs, and she helped older people, her parents told WFAA. She had struggled with addiction on and off, had recently left her husband and was living on her own, and was staying at the same Euless motel when she disappeared. "She'd call and say, 'Yeah, I'm here. Don't worry about it,'" her father said. Her mother said she had simply been in the wrong place at the wrong time. Her sister, speaking in court, called her lovely, strong and outgoing.
Lauren Phillips was 34, the only child of her mother and the mother of two teenage sons. When she was well she worked in home health care and in extended care facilities, her mother told CBS Texas. She had struggled with mental health problems and with methamphetamine addiction, and had been clean for about 10 years before drugs came back into her life. Her mother said she was loving and trusting and liked to help elderly people, and that she had met Thornburg while he was handing out church fliers; she believed her daughter had befriended him because she needed a place to stay. A friend drove her to the Euless motel. "She trusted this man and lost her life," her mother told WFAA. Her aunt told the court after the sentencing that before her addiction Lauren could make anyone laugh.
Prosecutors said at trial that Thornburg brought each of the three to his motel room separately over about seven days. The indictment documents, as reported by CBS Texas, alleged that he killed Lueras and Mathis with a knife and strangled Phillips. Surveillance video showed an SUV at the scene in Fort Worth late on September 21 and again early the next morning, the Associated Press reported. The Texas death row record gives the date of the offense as September 21, 2021.
The remains were found on September 22. Surveillance cameras near the scene had recorded a Jeep Grand Cherokee from the 2005 to 2010 model years. Fort Worth detectives cross-referenced nearly 7,000 such vehicles in the area and narrowed them to one registered to Thornburg, NBC News and WFAA reported. His name already meant something to them: he had been the main person of interest in Mark Jewell's death in May.
Video from the Euless motel was part of the evidence. Police tracked Thornburg to Arlington, where he was working, and asked him to come to the station. He was arrested on a Monday, the Associated Press reported on September 29, 2021, and charged with capital murder. Police said he confessed.
At a news conference after the arrest, Fort Worth Police Chief Neil Noakes praised the detectives and said the case "could have been cold case if not for their diligent efforts." Sergeant Joe Loughman of the homicide unit said the case was unlike anything he had seen in his time in the unit, and that Thornburg had given no clear reason for the killings. He was held in the Tarrant County Jail on a 1 million dollar bond.
According to the arrest warrant, Thornburg told detectives that he had an in-depth knowledge of the Bible and believed he was being called to "commit sacrifices." In a video recorded in September 2021, he said he knew the people he had killed and that they needed to be sacrificed for religious reasons, the District Attorney's Office said.
He did not stop at the three. He told police that he had killed Mark Jewell, that he had then uncapped a natural gas line in the house and lit a candle, the Associated Press reported from the warrant. And he said he had "sacrificed" a girlfriend in Arizona. Records showed she had been reported missing. By September 29, 2021, CBS Texas had identified her, from her family's public posts, as Tanya Begay.
CBS Texas reported that the arrest could answer her family's four-year search, and a spokesperson said the Navajo Nation police were leading the investigation into her disappearance. The FBI later told 12 News that her case remained open and that she had not been found.
In October 2021 a Tarrant County magistrate, Judge Nelda T. Cacciotti, ruled that there was "reasonable cause to believe" Thornburg had a mental illness or an intellectual disability. She ordered the county's mental health authority to interview him and report within four days on whether he had a mental illness or intellectual disability, whether there was evidence he might be incompetent to stand trial, and whether treatment was recommended, WFAA reported. The result of that evaluation was never made public. CBS Texas reported in February 2022 that questions had been raised about his fitness to stand trial. His case went to trial in 2024.
On December 13, 2021, a Tarrant County grand jury indicted Thornburg on one count of capital murder covering the deaths of David Lueras, Lauren Phillips and Maricruz Mathis, according to the Associated Press. CBS Texas reported the indictment as returned in Criminal District Court No. 3.
On February 18, 2022, a Tarrant County grand jury indicted him on charges of murder and arson in the death of Mark Jewell, CBS Texas reported. The charges carried a possible life sentence.
In March 2022, according to the Associated Press and NBC 5, a federal grand jury in the District of Arizona indicted Thornburg on charges of first-degree murder, assault with intent to commit murder and assault resulting in serious bodily injury. The charges concerned a killing on the Navajo Nation in March 2017. The indictment identified the victim only by the initials T.T.B. Neither report said whether that case concerned Tanya Begay, and the outcome of the federal case has not been reported.
On May 16, 2022, the Tarrant County Criminal District Attorney, Sharen Wilson, announced that her office would seek the death penalty. "The decision on whether or not to seek the death penalty is a crucial decision this office makes," she said in a statement quoted by NBC 5. "The death penalty is reserved for the worst of the worst criminals." Assistant district attorneys Kim D'Avignon and Jim Hudson were assigned to the case. Thornburg remained in jail on bonds totaling 1.2 million dollars.
Maricruz Mathis's mother had already said publicly that she believed he deserved death. "Please, don't let him out on the street again," she told WFAA.
The case was the first death penalty trial in Tarrant County since 2019, WFAA reported.
The trial opened on Thursday, November 7, 2024, in Criminal District Court No. 3 before Judge Douglas A. Allen. The prosecutors were Kim D'Avignon, Emily Dixon and Amy Allin. Thornburg's lawyers, among them Bob Gill and J. Warren St. John, did not dispute that he had killed the three. Their defense was insanity.
Gill told the jury that Thornburg's troubled childhood and his religious beliefs had produced a "deeply entrenched delusion" that God had commanded the killings, The Dallas Morning News reported. The defense said he was psychotic and heard voices, and that he believed the killings were religiously required.
The prosecution answered that whatever his beliefs, he knew what he was doing. "This crime is crazy. Yes, it is. No doubt about that," Dixon told the jury. Thornburg, she said, "is not insane, though." Allin described him as someone who used Scripture as "his weapon of choice" to get vulnerable people to lower their guard, the District Attorney's Office said, and as the kind of friend who offers you a place to sleep. Dixon said all three had been lured to their deaths in that motel room.
On Wednesday, November 20, 2024, on the eighth day of testimony and after about two hours of deliberation, the jury found Thornburg guilty of capital murder and rejected the verdict of not guilty by reason of insanity that his lawyers had asked for. A capital murder conviction left the jury two choices, life in prison without parole or death, The Dallas Morning News noted.
The punishment phase began the next day, and the killings of Mark Jewell and Tanya Begay were raised in court, Fox News reported. A cousin of Tanya Begay gave a statement to the court, NBC 5 reported.
The defense now argued that Thornburg's conduct stemmed from fetal alcohol syndrome and the damage done to him before birth. "From the get-go, he was doomed in the womb," St. John told the jury. Defense experts testified to partial fetal alcohol syndrome and childhood trauma. Thornburg's uncle described his upbringing and told the jury that Thornburg believed he was doing right because of the voices he heard. St. John said his client was now on the right medication, that his psychosis had eased, and that he should be allowed to live out his life in prison. The defense asked the jurors whether executing a psychotic or delusional man was just.
The prosecution said he was using mental illness as a shield. D'Avignon called the defense experts' methods unscientific. Prosecutors pointed to his own statements to show planning: he had planned how to hide the crimes and destroy evidence. "You don't almost get away with two murders with a lack of executive functioning," the prosecution told the jury, according to FOX 4. Prosecutors also argued that he would remain dangerous in prison and told the jury he had been making weapons in his cell during jury selection, NBC 5 reported. D'Avignon said what he did was methodical and sadistic. Allin called him evil.
On Wednesday, December 4, 2024, after only a few hours of deliberation following closing arguments, the jury found that he would be a future danger and sentenced him to death, FOX 4 reported. The verdict was read shortly after 4 p.m., and Judge Allen pronounced the sentence of death. Thornburg showed no reaction. Several jurors wiped away tears.
The families then spoke. Maricruz Mathis's sister told Thornburg, "Your actions have caused a lot of pain," and said that even with justice, "we will still be missing our loved ones." She said she hoped he might find forgiveness in heaven but did not believe she could forgive him herself. David Lueras's mother read a statement on behalf of all the families, saying their faith had carried them through the trial, and outside the courthouse she spoke the name of each victim aloud. Lauren Phillips's aunt remembered a woman who could make anyone laugh. Tanya Begay's sister said the family still needed closure and wanted to bring her home.
The District Attorney's Office, by then led by Phil Sorrells, reported the verdict in its winter 2024 newsletter and credited the three trial prosecutors, investigators and victim advocates who worked on the case.
Thornburg was received on Texas death row on December 5, 2024, as prisoner number 999635. His direct appeal, Jason Alan Thornburg v. The State of Texas, No. AP-77,128, was set for oral argument before the Texas Court of Criminal Appeals at 9 a.m. on October 14, 2026. No decision had been reported by October 23, 2026.
The Jewell indictment for murder and arson remained pending as of the 2024 trial coverage, and no trial date for it had been reported. No charge in New Mexico or Arizona naming Tanya Begay as a victim has been reported. Her body has never been found.
Tanya Begay's case drew attention in Arizona to how disappearances of Native women are handled. Navajo Nation Council Delegate Amber Kanazbah Crotty, a member of the Missing and Murdered Diné Relatives task force, told 12 News that the FBI generally becomes involved only when foul play is suspected, and that families often have to search on their own. Arizona State Representative Jennifer Jermaine introduced a bill, HB2142, that would require law enforcement agencies to contact federal partners once an adult had been missing for 30 days. 12 News also cited a November 2020 report by Arizona State University's Violent Victimization Lab finding that Indigenous women are murdered at about 10 times the national average.
Proven by a jury verdict (appeal pending): the capital murder of David Lueras, Maricruz Mathis and Lauren Phillips in Euless in September 2021.
Charged and untried: the murder of Mark Jewell and arson of the house, May 21, 2021. The medical examiner could not determine how Jewell died. The account of his death rests on what Thornburg told police, as reported from the warrant.
Confessed, according to police, and never tried: the death of Tanya Begay, who disappeared in March 2017. Her body has not been found. A federal indictment in Arizona in March 2022 concerned a March 2017 killing on the Navajo Nation of a victim identified only by initials; no report connected that indictment to her by name, and its outcome was not reported.
Details that differ between sources: David Lueras's surname is spelled Luera in some reports, and Maricruz Mathis is also called Maricruz Reyes-Mathis. The capital murder indictment is dated December 13, 2021, by the Associated Press, while CBS Texas reported it as returned on a Tuesday. Accounts of the arrest differ on place: the Associated Press and WFAA said he was found working in Arlington and brought to the station, while NBC News reported that detectives found him at the Euless motel. A police sergeant said he had no extensive criminal or violent history, while 12 News reported a 2015 vehicle theft conviction.
August 27, 1980: Jason Alan Thornburg is born.
2014: a carjacking case in Pima County, Arizona, is mentioned in later reporting; its outcome is not reported.
2015: convicted in a vehicle theft case; paroled in February 2016.
February 18, 2017: Gallup police answer a domestic disturbance call involving Tanya Begay and Thornburg.
March 2, 2017: Tanya Begay is last seen leaving Tohatchi, New Mexico, with Thornburg; she calls her mother the next day from Leupp, Arizona.
March 19, 2017: her mother reports her missing to Gallup police.
March 21, 2017: Thornburg is arrested in Gallup; he is not treated as a suspect in her disappearance.
June 22, 2017: the New Mexico assault charges are dropped.
May 21, 2021: Mark Jewell, 61, dies when the Fort Worth house he shared with Thornburg explodes.
Late July 2021: Thornburg moves into a motel in Euless.
September 2021: David Lueras, Maricruz Mathis and Lauren Phillips are killed in his motel room over about seven days.
September 22, 2021: the remains of the three are found in Fort Worth.
Late September 2021 (a Monday, per the Associated Press): Thornburg is arrested and charged with capital murder; police say he confessed to the three killings and two others.
October 2021: a magistrate finds reasonable cause to believe he has a mental illness or intellectual disability and orders an evaluation.
December 13, 2021: indicted for capital murder.
February 18, 2022: indicted for murder and arson in Mark Jewell's death.
March 2022: a federal grand jury in Arizona returns an indictment over a March 2017 killing on the Navajo Nation.
May 16, 2022: District Attorney Sharen Wilson announces that her office will seek the death penalty.
November 7, 2024: trial opens in Criminal District Court No. 3.
November 20, 2024: jury finds him guilty of capital murder and rejects the insanity defense.
December 4, 2024: jury sentences him to death.
December 5, 2024: received on Texas death row.
October 14, 2026: oral argument set in his direct appeal before the Texas Court of Criminal Appeals.
October 23, 2026: on death row; appeal undecided; the Jewell charges untried; Tanya Begay still missing.