Liam Quinn

William Joseph Quinn, known as Liam Quinn, (born 1949) is an American former volunteer in the Provisional Irish Republican Army who shot dead Stephen Tibble, an off-duty police officer, in London on 26 February 1975.

Tibble saw Quinn fleeing from the police after he had been noticed acting suspiciously near a house in which Quinn and members of the Balcombe Street Gang were later found to have been preparing bombs. The unarmed Tibble chased Quinn on his motorbike and, while attempting to stop him, was fatally shot twice in the chest. Provided by Wikipedia