Andrés Ulises Castillo Villarreal was born in 1980 in Mexico and spent most of his life in Chihuahua City, where he later committed a series of violent sexual homicides. Public records regarding his early education and employment are limited. However, psychological evaluations conducted after his arrest revealed that Castillo had been subjected to repeated sexual abuse during childhood, a factor that investigators and profilers believe played a significant role in shaping his later criminal behavior.

As an adult, Castillo worked intermittently as a narcomenudista, or small‑scale drug dealer, primarily distributing methamphetamines. This activity brought him into contact with marginalized individuals, many of whom struggled with addiction and unstable living conditions. Authorities believe Castillo deliberately targeted such individuals because they were less likely to be immediately reported missing and more vulnerable to manipulation.

Castillo lived in modest housing within working‑class neighborhoods of Chihuahua City. In some cases, he shared residences with acquaintances or victims. According to investigators, he led a largely unremarkable outward life and did not attract significant attention from law enforcement prior to the discovery of the murders in late 2015.

Between 2009 and 2015, Andrés Castillo carried out a series of brutal sexual murders in Chihuahua City. His confirmed victims were adult men, many of whom were known to use methamphetamines. Castillo lured his victims with promises of free drugs, driving them either to his home or to isolated areas on the outskirts of the city.

Once alone with the victims, Castillo would drug and intoxicate them before striking them on the head with a blunt object to incapacitate them. He then sexually assaulted the victims and delivered further blows to the head until they were dead. Afterward, Castillo dismembered the bodies using a coping saw, a tool he used consistently throughout the murders. He transported body parts in a wheelbarrow and abandoned them in vacant lots, dry streams, or partially buried locations. In at least one case, he buried a victim beneath the floor of his own home. A distinctive signature of his crimes was the placement of children’s toys, often parts of a tricycle, next to the mutilated remains.

The first confirmed victim was Lorenzo Ernesto Olivas Barrios (22), who disappeared on November 13, 2015 after leaving his relatives’ home to buy dinner. His dismembered remains were discovered between November 16 and 17, 2015, in the Urban Development neighborhood. Investigators later determined that Olivas had met Castillo at a bar earlier that night and accompanied him home, where he was drugged, raped, beaten to death with a hammer, and dismembered. Castillo forced a teenager, under threat of death, to help dispose of the remains and later sexually assaulted the teen.

On December 13, 2015, the mutilated remains of Daniel Alfonso Rodríguez Morales (22) were found in the same area. The similarities between the two crime scenes, including dismemberment patterns and toy placement, indicated the same perpetrator. Rodríguez had been drugged and killed by repeated blows to the head, with additional gunshot wounds inflicted. Castillo forced witnesses to assist in disposing of the body under threat of violence.

The final confirmed victim was Fernando Valles Gandarilla, whose body was discovered on December 18, 2015, buried beneath the floor of Castillo’s room. Castillo had drugged, raped, and beaten Fernando to death, destroying his skull and concealing the remains with cement and rocks.

Following these discoveries, authorities intensified their investigation. Castillo was arrested on January 6, 2016, in the Vista Cerro Grande neighborhood while in possession of methamphetamine. During questioning, he confessed to killing 12 people, though prosecutors believe he may be responsible for up to 20 murders dating back to 2009.

On December 5, 2017, Andrés Ulises Castillo Villarreal was sentenced to 120 years in prison for multiple counts of homicide, sexual assault, and related crimes. He remains incarcerated in Mexico.