El Goyo Cárdenas, one of Mexico's most infamous serial killers

Gregorio Cárdenas Hernández was a 26 year-old young man from Veracruz who went on to became one of the most notorious serial killers in Mexico after killing at least four underage girls by strangling them to death. Gregorio even stalked one of his victims, a high school student by the name of Graciela Arias.

The other three victims were prostitutes he picked up on the street, took them back to his home, and then beat and strangled them to death, and buried their remains in his backyard in Mexico City's Tacuba neighborhood.

El Goyo Cárdenas, as he became known, received a scholarship from the Mexican state-owned oil company Pemex to study Chemical Science, but his horrifying murders were eventually discovered.

According to statements made by his mother, Vicenta Hernández, as well as psychologists and criminologists who studied him, Goyo always suffered from neurological problems. Doctor Gonzalo Lafora claimed that the killer always showed pathological signs that were most likely inherited from his father and grandfather.

Goyo is also believed to have had an extremely unhealthy relationship with his mother, who was incredibly aggressive and constantly reprimanded him well into his adult life. Despite these problems, Goyo had an above normal IQ, which allowed him to excel in school.

Photo: Goyo's nephew, Santos Félix Cuicas, seen here in an interview with EL UNIVERSAL saying that his “uncle is a good person, he's always giving his children good advice.”

According to Lafora, Goyo began his obsession with prostitutes at the age of 18, contracting several venereal diseases along the way. In 1940, he began a romantic relationship with Virginia Leal whom he met at a party and who later became his lover. Virginia, a short while later, abandoned him.

Photo: El Goyo seen in a Mexico City prison in December 1942.

Goyo was forced to marry Gabina González after her parents went to the courts demanding that her marry her after catching them having sex. They eventually divorced after Gabina was caught having extramarital affairs. This divorce, together with Virginia who abandoned him, are thought to be the catalysts that led to Goyo developing hate towards women and sent him into severe state of depression.

Photo:Goyo Cárdenas seen at the entrance of the Oriente penitentiary in Mexico City moments after being freed in 1976.

Dr. Quiroz Cuarón reported that once at the Lecumberri federal prison in Mexico City, Goyo showed feminine mannerisms and found several photographs of him dressed as a woman.

Goyo was finally diagnosed while in prison with paranoid schizophrenia.

Photo: Mexico's lower chamber of congress gave Goyo a standing ovation after a speech he gave on September 23, 1976. EL UNIVERSAL released an article about this bizarre story the day after the events took place.