Mario James Jerrell Normore was born on April 23, 1991, in Oklahoma City, Oklahoma. Little is known about his early life. As he grew older, he became involved in criminal activities. He started committing crimes in 2009 and was associated with the Rollin' 20 Crips, which is a part of the larger Crips gang.

In 2010, Mario was convicted of robbery. He was sentenced to eight years in prison for this crime. After serving some time, he was released from prison in May 2017. Following his release, he found a job at a recycling plant. It was there that he met Bashar Burks, who was 27 years old at the time.

On July 10, 2017, Mario James Jerrell Normore got a ride from Bashar Burks and his girlfriend, Ashley Easton. During the ride, Normore and Burks argued. Believing Burks was reaching for a gun, Normore took out his own gun and shot Burks in the head. He then shot Ashley Easton. Their car was later found on fire with Burks' body inside. The next day, police discovered Easton's body in a ditch, leading them to realize that both were murder victims.

After these murders, Normore enlisted his cousin, Brandon Lee Butler, to help him rob several banks in Oklahoma City. On August 18, 2017, they visited the home of 20-year-old Searra Howe to steal her car. They kidnapped Howe and drove her to a forest near Jones. Butler did not want to kill Howe and planned to scare her instead, but Normore grew impatient and shot her in the head. She was reported missing the next day, and her remains were found two months later.

On October 3, 2017, Normore went to the apartment of James Steven Knowles, a 57-year-old maintenance man. He shot Knowles and disposed of his body, which has never been found. Normore later gave different reasons for this murder, suggesting he shot Knowles either because he was a snitch or over a dispute about $20.

Normore aimed to kill Butler but was unsuccessful when his gun did not fire. On October 27, 2017, he was arrested after being connected to ten bank robberies. Initially, he was not linked to the murders. Almost a year later, authorities connected him to the homicide cases, and he was charged with four counts of murder.

In 2019, during a court hearing, Butler testified that Howe had begged for her life before Normore shot her. In September 2018, Normore and other inmates staged a riot in the Oklahoma County Detention Center. They attacked guards and tried to escape. In March 2022, he was involved in another attempted escape where he assaulted a guard.

On March 21, 2023, to avoid the death penalty, Normore pleaded guilty to four counts of murder and ten counts of robbery. He received four consecutive life sentences without the possibility of parole. This plea deal brought a sense of closure to the families of the victims, despite their concerns about the decision not to pursue the death penalty.