Similar to Teresa Lisbon in the CBI chain of command Bosco, a married man, worked under Virgil Minelli, the administrator of the CBI, and led his own team of agents. Lisbon and Bosco shared a dark secret from the past involving a case they both worked on five years ago when Lisbon, a new agent under Bosco, was in the news heralded as a "saint." In Episode Black Gold and Red Blood Lisbon threatened Bosco that she'd "talk" -- tell all -- if Bosco wouldn't comply with a demand, the implication being that there was a cover-up which, if known, would ruin both Bosco's and Lisbon's careers. Jane guessed at the end of the episode that Bosco killed a man, a bad guy, who he couldn't catch any other way, and that Lisbon found out after the fact and didn't tell anybody because the bad guy deserved it. Based off of Lisbon's expressions and Jane's likelihood for being correct, it can be concluded that he was correct.
When Patrick Jane told Lisbon once that Bosco was in love with her, his comment surprised a sincere expression of disbelief out of her. Jane's insight was proven correct later by Bosco's declaration to Lisbon while on his deathbed.
Bosco and Patrick Jane had an antagonistic relationship based on lack of trust. Jane didn't trust Bosco to properly investigate the Red John case, and Bosco viewed Jane as generally untrustworthy and unreliable: as a loose cannon rather than as a professional. As a result, Bosco was mostly immune to Jane's charms, though they started to like one another after being forced to cooperate.
Bosco and his team were killed by his secretary Rebecca, who turned out to be an accomplice of Red John's. She was killed by Red John or one of his agents before she could reveal anything about Red John.
Bosco's team members were dead at the scene, but Bosco himself survived the attack for a couple of days before dying from his injuries. Before his death, he told Lisbon "I love you." He also reconciled with Jane, and told Jane that when he caught Red John to kill him, not arrest him, and protect Lisbon.
Following Bosco's death, Virgil Minelli retired from the CBI.
Behind the ScenesEdit
Sam Bosco was portrayed by actor and theatre director Terry Kinney.