Lead police detective returns to witness stand in Zimmerman trial over teen's shooting death

The lead police detective who investigated Trayvon Martin's fatal shooting last year is returning to the witness stand.

Sanford Police detective Chris Serino testifies for a second day Tuesday about his investigation into the fatal shooting of the Miami teenager by George Zimmerman, a neighborhood watch volunteer.

The 29-year-old Zimmerman is pleading not guilty to second-degree murder. He claims he acted in self-defense.

Jurors on Monday heard a series of recorded police interviews of detectives questioning Zimmerman about his confrontation with Martin in a gated community in central Florida.