An investigation has been launched into an in-custody death that happened while a man was being detained following an altercation at a downtown San Diego bar Saturday night.

A man accused of causing a disturbance inside a San Diego bar, then striking and biting a security guard, died after he stopped breathing while struggling with the guard and then officers, law enforcement said Sunday.

Officers responding to reports of an altercation and gunfire at a residence in the 1600 block of Chalcedony Street about 10:15 p.m. Sunday found 31-year-old Richard Herrman outside the condo with a gun, according to the San Diego Police Department.