Juana Dayanara Barraza Samperio was born on December 27, 1957, in Epazoyucan, Hidalgo, a rural area north of Mexico City. She had a difficult childhood. Her mother, Justa Samperio, was an alcoholic. It is reported that her mother exchanged Juana for three beers to a man who abused her. This man was responsible for Juana's conception. Justa had four children in total, but her eldest son died from injuries he sustained in a mugging.

Growing up, Juana faced many hardships. She was interested in lucha libre, a type of Mexican professional wrestling. This interest grew into a career as she became a professional wrestler. She fought under the ring name "La Dama del Silencio," which means "The Lady of Silence." Juana was known for her strong presence in the ring.

Despite her tough beginnings, Juana had a passion for wrestling. She spent much of her time involved in lucha libre, gaining recognition in the sport.

Juana Dayanara Barraza Samperio, known as La Mataviejitas, was involved in a series of crimes targeting elderly women in Mexico City. All her victims were women aged 60 or older, many of whom lived alone. Barraza would often gain their trust before attacking them. She would bludgeon or strangle these women and then rob them.

Authorities believed that Barraza posed as a government official to offer help with social welfare programs. This way, she could enter their homes without raising suspicion. The investigation into her crimes began in earnest when it became clear that a serial killer was active in the city. However, initial responses from the police faced criticism for not taking the situation seriously.

By late 2005, investigators had gathered witness statements suggesting that the killer dressed in women's clothing to access the victims' apartments. They received descriptions of a large woman wearing a red blouse leaving a crime scene. As the investigation progressed, officials began to suspect that the killer might be female, despite earlier assumptions that it was a male.

A significant breakthrough occurred on January 25, 2006. Barraza was caught fleeing from the home of her latest victim, Ana María de los Reyes Alfaro, who was 82 years old and had been strangled. When police detained her, she was carrying a stethoscope and identification that linked her to social work.

After her arrest, fingerprint evidence tied Barraza to multiple murders. Barraza confessed to killing Alfaro and three other women but denied involvement in the remaining cases. This led to her trial in 2008, where prosecutors claimed she was responsible for as many as 40 murders. Eventually, Barraza was found guilty of 16 murders and several counts of aggravated burglary, receiving a sentence of 759 years in prison.

Barraza's time in prison saw her take on various roles, including working as a gym instructor. She even managed to get married and then divorced while serving her sentence.