Robert Lynn Pruett was born on September 18, 1979, in Houston, Texas.

Robert Lynn Pruett was convicted of the murder of correctional officer Daniel Nagle at the McConnell Unit in Texas. The incident occurred on December 17, 1999. Nagle was known for advocating better conditions for prison staff. Just two weeks before his death, he made a statement suggesting that someone might need to die for the system to take notice of the issues inside Texas prisons.

Pruett, who was already serving a 99-year sentence for a previous murder, consistently denied any involvement in Nagle's death. The main evidence against him came from testimony provided by other inmates. Some of these witnesses were believed to have received deals from the state, which raised concerns about the reliability of their statements.

There was no physical evidence that directly linked Pruett to the murder. When the murder weapon, a prison shank, was tested for DNA, the results were inconclusive. Pruett claimed he was framed by corrupt inmates and guards who may have had their own motives for the crime.

Following his conviction on April 24, 2002, Pruett faced multiple legal challenges, but his appeals were largely unsuccessful. He received four stays of execution over the years. Despite his claims of innocence and arguments about the validity of the evidence used against him, Pruett was executed by lethal injection on October 12, 2017. His final death warrant was signed in June 2017 after numerous appeals were denied.