Brancato, who played a wannabe mobster on the HBO hit "The Sopranos," says he was suffering from heroin withdrawal when he and Steven Armento went to an apartment where the actor had obtained drugs before.
The 32-year-old Brancato is charged with second-degree murder in the 2005 shooting death of Officer Daniel Enchautegui.
Authorities say Armento and Brancato broke into the basement apartment to steal prescription drugs after a night of drinking at a strip club. Enchautegui, who lived next door, came out to investigate.
Brancato began his testimony Monday by describing his history of drug addiction that began while working on the 1993 film "A Bronx Tale."
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