Alfredo Rolando Prieto was born on November 18, 1965, in San Martín, San Salvador, El Salvador. He was the son of Arnoldo and Teodora Prieto and had five siblings. His family faced many challenges, especially financial ones, and they lived in poverty during his early years. This was a difficult time in El Salvador due to the Football War, which affected many families like his.

In 1975, when Alfredo was still a child, his mother left El Salvador to escape her husband’s abuse. She emigrated to the United States to seek a better life for herself and her children. During the Salvadoran Civil War, Alfredo witnessed the violence and chaos around him. He saw many civilians being killed, including his grandfather. This exposure to trauma would later lead to Alfredo being diagnosed with Post-Traumatic Stress Disorder (PTSD).

In 1981, Alfredo's mother returned to retrieve her children from El Salvador. They settled in Pomona, California, where he and his siblings attended Pomona High School. As he grew older, Alfredo struggled with drug and alcohol addiction during his high school years. Around this time, he and his brother Guillermo became involved with a local gang called "456 Island Piru." Alfredo dropped out of school and married Sandra Figueroa, who was connected to the gang. They had their first child in 1984.

In August 1984, Alfredo was involved in a shooting incident in Ontario, California. He claimed that he was motivated by jealousy when he suspected his wife of cheating. After being found guilty of the shootings, he received a minor sentence because the victims were gang members.

Alfredo was released from prison in 1987. He then moved to Arlington County, Virginia, where his father had relocated after serving a murder sentence in El Salvador. In Arlington, Alfredo found work and had another son with a different partner. However, in late 1989, his father was arrested for raping a woman. In February 1990, Alfredo left Virginia and returned to California.

Early in the morning on September 2, 1990, Alfredo Prieto, along with Vincent Lopez and Danny Sorian, committed a robbery in Ontario, California. They took Anthony Rangela hostage and drove him to his home. At Rangela's house, they kidnapped his aunt, Emily D., her daughter, Lisa H., and Lisa's friend, Yvette Woodruff. They drove the women to the outskirts of the city. During the drive, Lopez decided to leave the group.

Lopez was replaced by Ricardo Estrada, whom they met while buying gas. In an abandoned building in an industrial area, Prieto and his accomplices raped the women. Prieto shot and killed Yvette Woodruff. Meanwhile, Sorian and Estrada stabbed Emily D. and Lisa H. Despite suffering severe injuries, Emily D. and Lisa H. survived and were able to call the police. The police discovered Woodruff's body the same day, while the car used in the crime was recovered days later.

The police arrested Prieto and his accomplices between September 6 and September 22, 1990, after informants alerted them about the crime. A pistol that belonged to one of the victims was found at Prieto's apartment and was identified as the murder weapon.

Prieto was charged with first-degree murder, rape, kidnapping, and robbery. He was found guilty and sentenced to death on January 21, 1992. Prieto was then taken to San Quentin State Prison, where he spent 14 years on death row.

In 2005, a law mandated that all convicts submit DNA samples, which led to Prieto's DNA being entered into a national database. In early 2006, his DNA was linked to eight additional murders that took place between 1988 and 1990. These included the rape and murder of 24-year-old Veronica "Tina" Lynn Jefferson, the murder of 22-year-olds Rachael Raver and her fiancé Warren Fulton III, and the murder of 27-year-old Manuel Sermeno.

On May 5, 1990, Prieto was also linked to the murders of 19-year-old Stacey Siegrist and her fiancé Tony Gianuzzi. Siegrist was sexually assaulted before being shot. Prieto killed Lula Mae Farley on June 2, 1990, in an alley. After witnessing his wife’s murder, Herbert Farley was abducted and later found shot to death.

Following these revelations, Prieto was extradited from San Quentin to Virginia to face more charges. His first trial for the murders of Raver and Fulton began in 2007, and he was initially found guilty. However, the trial ended in a mistrial when a juror claimed peer pressure influenced the verdict. Prieto was retried in 2008, convicted, and given two death sentences. His lawyers appealed, leading to a Supreme Court ruling that overturned the sentence due to a jury verdict form error. He was resentenced to death again.

In a subsequent trial, his attorneys argued he was intellectually disabled, but prosecutors demonstrated that he had performed well in school and adapted socially. He was sentenced to death for a third time in 2010.

On October 1, 2015, Prieto was executed by lethal injection at the Greensville Correctional Center. His lawyers attempted to delay the execution, arguing that the drugs used were unsafe, but their lawsuit was dismissed.