In September 1942 Mexico City learned that four young women had died in Tacuba, in the north of the capital, and that a 27-year-old chemistry student had confessed to their deaths. The student was Gregorio Cárdenas Hernández, known for the rest of his life as Goyo Cárdenas. He was on a scholarship from Pemex, the national oil company, and the press described him as a thin, shy young man. Within two weeks the main daily papers had turned him into the most talked-about criminal in the country. The historian Juan de Dios Vázquez, writing in a UNAM journal in 2011, called him the first Mexican serial killer.
The case never reached a verdict. Psychiatrists disagreed about whether he was insane, he was sent back and forth between the Lecumberri prison and the La Castañeda asylum, and he escaped once. He was never sentenced. In September 1976, after 34 years in custody, a judge ordered his release for lack of proof, according to Vázquez, although several newspapers describe the release as a pardon from President Luis Echeverría. Two weeks later the interior secretary presented him to the Chamber of Deputies as proof that a man could be rehabilitated, and the deputies applauded. He spent his last two decades as a lawyer and died in California in 1999, having told interviewers that he was innocent.
Reports differ on where and when he was born. Excélsior, in a 2025 retrospective, gives Tierra Blanca, in the state of Veracruz, in 1916. Semanario Zeta of Tijuana, in a 2019 series on the case, says he was born in Mexico City. Vázquez writes that he came from Veracruz and moved to the capital after more than a decade of work for state companies and agencies.
Zeta's series says he had encephalitis as a child, links it to lasting neurological damage and to unusual behavior in his childhood, including cruelty to animals, and names his mother as Vicenta Hernández, describing her as a dominant figure in his youth. The same series says he had a very high IQ and stood out as a student, and Vázquez describes him as a notable student at UNAM's chemistry faculty.
Before the university he worked. Vázquez, citing his file, lists him as a stenographer for the national railways, Ferrocarriles Nacionales de México. He was active in the oil workers' union around the time of the 1938 nationalization: Vázquez describes him as a supporter and founder of the Pemex union who advised on the sharing out of posts after the expropriation, and in a 1992 interview with the magazine Proceso he called himself a minor union leader of Petróleos Mexicanos. By 1942 he was enrolled at UNAM's school of chemistry with a Pemex scholarship, and Vázquez places him in the new urban middle class that the economic policies of President Manuel Ávila Camacho were creating.
He had married young. Vázquez writes that two years before the killings he had secretly married a girl who was still a minor, and that the 1942 press dwelt on her humble background. Zeta says the marriage ended in divorce after about three years. The 1942 papers also portrayed him as a dutiful son who split his pay between his mother, his girlfriend and his wife, according to Vázquez.
Reports agree that four young women died between August and early September 1942. La Crónica de Hoy, in a 2022 essay by Diana Lizeth Hernández Meléndez, gives the names reported by police at the time: María de los Ángeles González, 16; Raquel Martínez León, 14; Rosa Reyes Quiroz, 16; and Graciela Arias, 21. Excélsior names only Graciela, giving her full name as Graciela Arias Ávalos.
Little is reported about the lives of the three girls. María de los Ángeles González is also given in Zeta's series by the name Bertha. Zeta reports that the second girl was first identified as Raquel, under a slightly different surname, and buried under that name, but that the young woman of that name was later found alive, so that the girl's true identity remained unknown. Rosa Reyes Quiroz is described in the same series as a minor.
More is known about Graciela Arias Ávalos. She was a student at the national preparatory school, the Escuela Nacional Preparatoria, and Zeta says she was in the chemistry track of the UNAM bachillerato. Her father was a criminal lawyer. Excélsior describes her as a friend whom Cárdenas had been courting, and La Crónica says he called her his girlfriend and told investigators that he loved her.
The dates of the deaths come from what he told investigators. La Crónica gives August 10, August 23 and August 29 for the three girls and the night of September 2 for Graciela. Zeta and La Razón de México put the first death on August 15. The reports describe the deaths as strangulation; one 2024 essay in La Razón gives a different cause for Graciela's death. All four were found in Tacuba in early September.
The case began with a missing-person report. On September 3, 1942, Graciela's father went to the police to say that she had not come home, according to La Crónica, and he named "Goyo" among her close friends, describing him as a chemistry student and Pemex employee who owned a small house in Tacuba. Her classmates said that on the rainy night of September 2 she had got into a Ford whose plates, B-901, they knew to be his.
Detectives went to look for him and found his mother. She told them that her son had gone mad and that she had placed him in a private psychiatric clinic the night before. Excélsior says that before this, visibly nervous, he had hinted at what he had done to a friend and to his mother. The police suspected that the clinic was an alibi. When they reached him there, he told them he was "the invisible man", with pills that could make people invisible, according to La Crónica; the detectives concluded that he was pretending.
Reports differ on where the clinic was. La Crónica places it in Tacubaya. The historian Andrés Ríos Molina, in a 2009 article on the La Castañeda asylum, says it was the private hospital that the psychiatrist Gregorio Oneto Barenque ran in the colonia Juárez, and that Oneto was the first psychiatrist to examine Cárdenas in detail, in September 1942. Ríos Molina writes that Oneto gave him sodium pentothal, obtained a full confession and reported it to the authorities. Excélsior gives the same sequence: Graciela's father and the police tried and failed to get answers from Cárdenas at Oneto's hospital, and after the psychiatrist gave him what the paper calls truth serum he confessed.
Detectives searched his house in Tacuba. La Crónica names the officer in charge as José Acosta Suárez. Police found some of Graciela's belongings, Excélsior reports, and on September 4 four young women were found dead in Tacuba, among them Graciela. One newspaper reported his jailing that day, according to La Crónica.
The discovery came at a tense moment. Mexico had entered the Second World War on the Allied side in 1942 after a German submarine sank the Mexican tanker Potrero del Llano, and the capital was living with blackout drills and new military service. La Crónica says that the case competed for front pages with the bill that created the Mexican Social Security Institute. On September 8, 1942, Excélsior's front page announced that a student had killed four young women, and the paper compared him to the French murderer Landru.
The press gave him many names. La Crónica lists the Mexican Bluebeard, the jackal and the troglodyte among them, and La Razón adds the "Totonac Bluebeard", a reference to his Veracruz origins. Vázquez writes that some front pages set him beside the Chalequero, who killed women in the capital under Porfirio Díaz, and the Tigre de Santa Julia, and that others cast him as a mad scientist with a private laboratory or as a local Jack the Ripper. One 1942 headline asked how he turned from a human being into a wild beast. The Taller de Gráfica Popular, the printmaking collective, produced a set of satirical skeleton prints about him for the Day of the Dead that year, according to La Crónica. Vázquez lists ballads, a radio serial and a stage play among the works the case inspired in its first years.
The case reopened an old argument about capital punishment, which had been abolished in 1931. Several legislators called for its return for killers like Cárdenas, Vázquez writes. The weekly magazine Tiempo asked its readers whether the death penalty should be restored in the Federal District, and La Crónica reports the result as 5,325 in favor and 4,838 against.
From the start the legal question was whether he was a criminal who could be tried or a sick man who should be treated. Excélsior describes a long legal process built around psychiatric examinations, because the answer would decide whether he went to prison or to a hospital. La Crónica counts 25 psychiatric studies in his file. Cárdenas later told Zeta's author, as the series reports, that he had been examined by roughly 48 or 50 doctors, and that their diagnoses ranged from schizophrenia and psychopathy to forms of epilepsy and paranoia.
His own account to the court was that he lost control. Before the 14th judge of the Fifth Criminal Court, he described sudden attacks of dizziness and heat with a whistling in his ears, after which a young woman would be dead at his feet, according to La Crónica. In a written statement of 1942, quoted by Vázquez, he said that "Cárdenas had turned into a wild beast", that his moral situation was unbearable and that he wanted to die. He also claimed, Vázquez writes, that he could turn into a bat and had invented a potion that made people invisible. Vázquez argues that he read the press coverage of his own case and drew on it to build a public persona.
His defense lawyer, Eduardo D. Casasús, presented the killings as the product of temporary insanity, Vázquez writes. The leading psychiatrists of the day took sides. La Razón reports that Leopoldo Salazar Viniegra, the director of La Castañeda, concluded that Cárdenas had trained himself to deceive the experts, and that the criminologist Alfonso Quiroz Cuarón later found that he had been aware of what he did. Quiroz Cuarón wrote the most complete study of him, Vázquez says, published in 1952 as Un estrangulador de mujeres. The Spanish psychiatrist Gonzalo Lafora also published an analysis of him in 1942. La Razón describes a heated and at times xenophobic dispute between the Mexican and Spanish doctors.
The examinations themselves were harsh. La Razón reports that he was given sodium pentothal injections, spinal fluid extractions and electroshock. Later diagnoses, Vázquez writes, included a bipolar disorder linked to epilepsy and chronic schizophrenia.
Vázquez writes that Cárdenas entered the Lecumberri penitentiary, known as the Black Palace, at noon on Saturday, September 13, 1942. His file at the asylum, held in the historical archive of Mexico's health ministry and described by Excélsior, records his admission to the Manicomio General de La Castañeda on November 8, 1942, under file number 27850. The file runs to 239 pages, records the case against him as homicide with clandestine burial, and says both criminal conduct and mental disorders. Because he was judged highly dangerous he was put in the ward for agitated patients. La Razón gives a different date, September 7, 1942, for his admission to the asylum.
He remained at La Castañeda for about five years; Vázquez gives the period as 1943 to 1947. Because he had been sent to the asylum, no sentence was ever issued in his case, Vázquez writes, and he was never formally found guilty.
On December 26, 1947, Cárdenas slipped out of his dormitory at La Castañeda, according to Excélsior, which draws on the asylum file. About a month later he was recaptured in Oaxaca, where he had been living as "Alejandro Hernández", teaching in local communities and calling himself "the enlightened one". La Crónica says the escape revealed that the authorities had judged a guard of his own too expensive.
Other reports give other dates. La Crónica places the escape at Christmas 1948. La Razón says he left the asylum with a nurse and another inmate and was arrested in August 1948 at Punta Palomas, Oaxaca, where he said he had been on vacation. Zeta says he was returned to Lecumberri on December 22, 1948.
After the escape he was not sent back to the asylum. Vázquez writes that he spent 1948 to 1952 in two cells at Lecumberri, the period of his book Celda 16, and from 1952 to 1976 lived in the prison's infirmary wards, the subject of his book Pabellón de locos.
Inside Lecumberri, Cárdenas built a second life. Zeta says he memorized the Penal Code and worked as a jailhouse lawyer; Excélsior says he studied law, art and painting and helped other inmates with their cases. Vázquez describes him painting portraits on commission, composing music, writing memoirs and weaving thread bags that were sold outside, and says that under later prison directors he ran the psychiatry and tuberculosis wards and several small businesses. Zeta says he supported his family with a grocery store he ran inside the prison.
He married while in prison. Excélsior says he married his second wife 22 years before his release. La Crónica says he had five children. Excélsior describes an abstract painting he signed at Lecumberri in 1973.
He wrote books. Vázquez lists Celda 16, Pabellón de locos (Diana, 1973) and Adiós, Lecumberri (Diana, 1979), along with a published diary, Una mente turbulenta, and an essay on the prison system, Campo de concentración. La Razón dates Celda 16 to 1970 and Una mente turbulenta to 1973 and mentions a weekly comic, built on crime stories from Lecumberri, issued under his name. Vázquez argues that these prison writings set out a quieter, more reflective figure than the one the 1942 press had created, and that Cárdenas presented his rehabilitation as his own work rather than the prison's.
His legal position did not change for decades. In 1972 his lawyer, Salvador Salmerón Solano, argued that he had already been held longer than the 30-year constitutional limit, Vázquez writes.
Lecumberri closed as a prison in 1976, and Cárdenas spent several months in the new Reclusorio Oriente, according to Excélsior and La Crónica. In September 1976, Vázquez writes, Judge Raúl Gutiérrez Márquez of Criminal Court 28 ordered his release for "falta de comprobación", lack of proof. Zeta gives the date he walked out as September 8, 1976.
Newspapers describe the release in other terms. Zeta says that after his family appealed, President Luis Echeverría granted him a pardon. La Crónica also speaks of a pardon from Echeverría. Excélsior says only that his defense secured his freedom in the first days of September. In a 1992 interview with Proceso, quoted by Vázquez, Cárdenas said he had been given a release paper declaring him innocent "because nothing was ever proved" against him.
After leaving prison he went to the Basilica of Guadalupe to pray and ask forgiveness, Excélsior reports, fulfilling a promise he had made to his wife when they married. He told reporters that he felt calm and that the ghosts of those women would no longer trouble his mind.
On September 23, 1976, the secretary of the interior, Mario Moya Palencia, appeared before the Chamber of Deputies to defend a proposed amendment to Article 18 of the Constitution that would allow prisoners to be transferred to their home countries. The official record of the session, the Diario de los Debates, shows that while answering a question from Deputy Enrique Álvarez del Castillo, Moya Palencia turned to the subject of rehabilitation and pointed to a man in the chamber. More than 30 years earlier, he said, that man had committed several crimes against society; in prison he had transformed himself, studied, written several books and raised a family, and now he had walked out to make a new life and return to the service of his community. He said he was glad to have him there, and named him as Gregorio Cárdenas Hernández. The printed record spells the surname "Cárdenos".
Excélsior reports that Cárdenas sat in the chamber's box of honor, that Moya Palencia called him an example for Mexicans without mentioning the women who had died, and that the deputies gave him a long ovation. Zeta says many deputies of the governing party stood to applaud and called him a clear case of rehabilitation. The session record shows applause at the end of the secretary's reply. Vázquez says that Quiroz Cuarón and the last director of Lecumberri both criticized the official story of his rehabilitation.
Cárdenas opened a law office in 1977 on the avenue named after Lecumberri and lived for most of the following years a few blocks from the old prison, Vázquez writes. He held an exhibition of his paintings, which Zeta says sold well. He completed his law degree at UNAM's ENEP Aragón campus about four years after his release, according to Excélsior; Vázquez says that his diploma is dated 1980, although Cárdenas said he had earned it in prison. He stayed out of public life, Excélsior says.
He was not silent about his past. In a 1989 interview with Proceso he said there had been no rehabilitation and that he was a normal man, and in a 1992 interview with the same magazine he denied the killings and suggested that his imprisonment had political roots in his union days, Vázquez writes. Zeta reports that a radio soap opera was made about his life and that he went to law over the play El estrangulador de Tacuba by Víctor Hugo Rascón Banda, which starred Sergio Bustamante, claiming the rights to his story.
He died on August 2, 1999, according to Excélsior and Zeta. Excélsior gives his age as 83 and the place as California; Vázquez says he died in a hospital in Los Angeles. La Crónica gives his age as 84.
Alejandro Jodorowsky's 1989 film Santa sangre was loosely based on his story, Vázquez writes. La Razón describes plays, films, documentaries, corridos and burlesque acts drawn from the case. Alfonso Quiroz Cuarón's study Un estrangulador de mujeres (1952) remains the best-known expert account, and his memoirs, transcribed by José Ramón Garmabella as El criminólogo, describe meeting Cárdenas after his release, according to La Razón.
Guilt. Cárdenas confessed in 1942, but no court ruled on the charges, according to Vázquez. Vázquez says no sentence was issued and that he was released for lack of proof; in his 1990s interviews Cárdenas denied the killings. Vázquez cites the 2010 book by Ríos Molina, who reports that under sodium pentothal Cárdenas denied the killings and blamed two friends, and who suggests he may have been innocent; Vázquez disagrees with that reading. La Razón says he never confessed. La Crónica says that recent research has reexamined his statements and questioned his guilt. Ríos Molina's own 2009 article, by contrast, says the pentothal session produced a full confession.
Sentence. Several newspapers describe a sentence. La Razón says he was sentenced to 35 years, and Excélsior refers to a term of more than 30 years. Vázquez, citing the court record of his release, says no sentence was passed.
Pardon or court order. Zeta and La Crónica say President Echeverría pardoned him. Vázquez says a criminal judge ordered his release for lack of proof. Excélsior attributes the release to his defense.
The congressional session. La Crónica places the ovation in the Senate and attributes to Moya Palencia a remark that both Cárdenas's fall into violence and his return from it were shaped by economic, political and cultural forces. The Chamber of Deputies record for September 23, 1976, places the appearance in the lower house and does not contain that sentence.
The second victim. La Crónica gives her name as Raquel Martínez León, 14. Zeta says the girl buried under the name Raquel was misidentified and that her identity remained unknown.
Dates. The first death is dated August 10 (La Crónica) or August 15 (Zeta, La Razón). The escape is dated December 26, 1947 (Excélsior), Christmas 1948 (La Crónica) or 1948 with a recapture in August (La Razón). His birthplace is given as Tierra Blanca, Veracruz (Excélsior) or Mexico City (Zeta), and his age at death as 83 (Excélsior) or 84 (La Crónica).
The clinic. La Crónica places the private sanatorium in Tacubaya; Ríos Molina places Oneto's hospital in the colonia Juárez.
1916: Gregorio Cárdenas Hernández is born in Tierra Blanca, Veracruz, according to Excélsior.
Before 1942: works as a stenographer for the national railways and is active in the oil workers' union.
Two years before the killings, by Vázquez's account: marries a girl who is still a minor; the marriage ends in divorce.
1942: studies chemistry at UNAM on a Pemex scholarship.
August 10 (or 15), 23 and 29, 1942: three girls die, by his later account.
September 2, 1942: Graciela Arias Ávalos, 21, is last seen getting into his car.
September 3, 1942: her father reports her missing.
September 4, 1942: four young women are found dead in Tacuba; he is jailed, by one newspaper's report.
September 8, 1942: Excélsior's front page reports the case.
September 13, 1942: he enters Lecumberri.
November 8, 1942: admitted to La Castañeda asylum (file 27850).
1942 to 1952: psychiatric studies by Oneto Barenque, Salazar Viniegra, Lafora and Quiroz Cuarón, among others; Quiroz Cuarón publishes Un estrangulador de mujeres in 1952.
December 26, 1947: escapes from La Castañeda (other reports give 1948); recaptured in Oaxaca.
1948: returned to Lecumberri.
1952 to 1976: lives in the Lecumberri infirmary wards; marries for the second time; writes several books.
1972: his lawyer argues that the 30-year constitutional limit has passed.
1976: Lecumberri closes; he is moved to the Reclusorio Oriente.
September 1976: released on a judge's order for lack of proof (some reports: a presidential pardon); September 8 by one report.
September 23, 1976: Interior Secretary Mario Moya Palencia presents him to the Chamber of Deputies as an example of rehabilitation.
1977: opens a law office in Mexico City.
1980: date on his UNAM law diploma.
1989: Santa sangre, loosely based on his story, is released; he tells Proceso there was no rehabilitation.
1992: tells Proceso he was innocent.
August 2, 1999: dies in Los Angeles, California.