<P> As the interim DA, McCoy came into conflict with Commissioner Reagan when he announced that the DA's office did not plan on prosecuting petty marijuana possession charges . </P> <P> A member of the DA's Investigations Unit who assists Erin with her cases . He is portrayed by James Lesure . In 1995, McBride's mother was murdered in an unsolved robbery . When Erin finds the case in a cold - case pile, she runs DNA found at the scene, which reveals what McBride already suspected, but was afraid to confirm: that his father had been responsible . </P> <P> A Detective for the DA's Investigations Unit who assists Erin with her cases . In "Friends in Need" it is revealed his cousin is Joey Ruscoli (Anthony DeSando) and his aunt is Sophia Ruscoli (Catherine Wolf). In "Good Cop Bad Cop" it is revealed that his mother is Lucille Abetemarco (Suzanne Shepherd). He is portrayed by Steve Schirripa . </P> <P> Jamie's first partner and Training Officer, Sergeant Tony Renzulli knows the beat of his precinct very well and often offers Jamie good advice when he needs it . He believes Jamie will make a great cop, and often pokes fun at him for abandoning a lucrative law career . He was also the Training Officer for Joe . In season 3, he moves to an apparent desk job managing the patrolmen of the 12th Precinct . He is married, and has a side job painting to make extra money; he is also a gambler, but quit after Frank bailed him out of a $3,000 debt (with it made clear that this is a one - time offer). He is portrayed by Nicholas Turturro . </P>

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