Black Bird (2022)

After Jimmy Keene is sentenced to 10 years in a minimum security prison without parole, he cuts a deal with the FBI to enter maximum-security prison for the criminally insane and befriend a suspected serial killer, Larry Hall (Paul Walter Hauser). Keene's job is to elicit a confession from Hall in order to slam the door on Hall's appeal and find the buried bodies of as many as eighteen women. But is Hall a serial killer? Or a serial confessor?