S4, E7: Voight (Jason Beghe) calls the team to investigate a homicide involving the only witness in a rape and murder case against an extremely young man, Oliver Tuxhorn (guest star Gus Halper). Intelligence looks into Tuxhorn's family and their finances as they try to determine if someone was paid to take out the victim. Meanwhile, Stone (guest star Philip Winchester) offers Antonio (Jon Seda) a job as lead investigator for the state attorney's office, and Burgess (Marina Squerciati) and Sorensen's (guest star Kevin Kane) body cameras capture a bizarre exchange with a man that they pull over.