Cesar Roberto Fierro was born on October 18, 1956. He grew up in a poor family in Mexico.

In February 1979, the body of taxi driver Nicholas Castanon was discovered by Texas law enforcement. His cab was later found in Ciudad Juárez, Mexico. Initially, two men were arrested as suspects in the case but were released due to lack of evidence. In late July, a man named Geraldo Olague informed the police in Juárez that he and Cesar Roberto Fierro had planned to rob Castanon. Olague claimed that during the robbery, Fierro shot and killed the taxi driver. It remains unclear how Olague came to be in contact with the police.

Following this information, the police in Juárez notified the El Paso police, who then traveled to Juárez to arrest Fierro. He was 23 years old at the time of these events. On February 15, 1980, Fierro was convicted of capital murder and sentenced to death. His case was controversial because Mexican police in Ciudad Juárez had arrested his parents, reportedly threatening them with torture unless he confessed. Fierro claimed that a police officer told him that if he signed a confession, they would let his parents go, but if he did not, they would be harmed.

At the trial, law enforcement from both Juárez and El Paso denied any misconduct. There was no physical evidence linking Fierro to the shooting. The conviction relied heavily on his confession and the testimony of a 16-year-old who had psychological issues.

In later years, Judge Sharon Keller of the Texas Court of Criminal Appeals described the coerced confession as a "harmless error." In 2003, the International Court of Justice issued a preliminary order blocking the United States from executing Fierro while a related case was being considered.

Fierro spent nearly 40 years in prison. On December 19, 2019, his death sentence was vacated due to problems with jury instructions during his trial. Prosecutors decided not to seek another death sentence. Fierro was subsequently resentenced to life in prison. On May 14, 2020, he was released on parole and returned to live with family in Mexico.