"Snyder jumps a call at 5 in the morning at the end of his shift and goes, 'Hey Bud,'" as he walked up to the driver's side of Forster's car, Key said.

"That's the kind of guy he was. There to defuse the situation, be nice, be polite. And it cost him his life."

Reynolds told jurors that the question they had to answer was whether Forster's mental illness left him unable to deliberate.

He detailed the problems in Forster's childhood, calling the parenting Forster received "disastrous."

Forster's best chance for help came when he was admitted to a mental health facility, but his father got him out early because Forster didn't like it there, Reynolds said.

"Did his bipolar manic phase of his illness impact his behavior, impact his cognition, awareness of his surroundings, so that he could deliberate?" Reynolds asked.

The night of the shooting, he said, Forster wasn't aware of anything going on after he was told he couldn't come inside his friend's house. “Trenton was is in such a state that he wasn’t aware of anything until ‘Hey bud,’ and he reacted,” Reynolds said.