Warning: spoilers for Mindhunter season 2 ahead.

While many of the serial killers mentioned in Mindhunter are household names, not all of them are as notorious as Ed Kemper, Charles Manson, and the BTK Killer, Dennis Rader. Season 2 has just been released and with it a whole new slew of murderers to focus on. One that stood out was William “Junior” Pierce — who didn’t become a serial killer until after he was released from prison.

In Mindhunter, Pierce largely serves as a potential suspect for the Atlanta Child Murders that ultimately reaches a dead end. Played by Michael Filipowich, Pierce is visited in jail by Agents Holden Ford (Jonathan Groff) and Jim Barney (Albert Jones) in the third episode. Claiming he speaks multiple languages, including “Libyan,” it becomes clear Ford’s intellectual approach does not work when it comes to Pierce, who reportedly has an IQ of 70, and Barney steps in to assist (and coax Pierce into talking with treats).

However, in real life, Pierce’s story has a lot more going on besides his love of snack foods. In 1970, Pierce was serving a 10 to 20-year sentence in a Georgia prison for a list of crimes including arson, burglary, receiving stolen property, and an attempted prison break. Pierce was only seven years into his sentence when he was released on parole despite staff psychologists classifying him as “dangerous.” The parole board ignored this and let him out of jail anyway.

In the one year he was on parole, Pierce murdered nine people across Georgia and South Carolina. One of the most high-profile murders he was convicted for was that of Margaret “Peg” Cuttino, the daughter of a South Carolina senator.

Pierce was rearrested on March 8, 1971. According to the Georgia Offender Database, he is currently imprisoned for murder with a maximum sentence of life in prison.