A 37-year-old man was shot dead in the Waterside area of Derry early this morning.
A gang of three or four men armed with a long-barrelled weapon gunned the man down in the Mildale Crescent area at around 12.20am.
The RUC is still trying to establish a motive for the attack.
The attackers are believed to have fled the scene at high speed in a four-door saloon.
Meanwhile, the RUC is also investigating a paramilitary-style punishment attack in Belfast last night.
A young man received gunshot wounds in the attack.