CAPE TOWN (Reuters) - Six people, including three young girls, were shot dead when suspected Moslem vigilantes opened fire on the house of an alleged drug dealer in a Cape Town suburb on Sunday evening, South African police said. Police spokesman Wickus Holtzhausen on Monday told Reuters the six were killed at the house of a suspected drug dealer know as Pinnochio in Woodstock suburb and said a seventh person was in critical condition in hospital. Cape Town has seen a series of clashes between gangsters and a religious movement seeking to wipe out the drugs trade. Holtzhausen said police suspected that the People Against Gangsterism and Drugs (PAGAD) Moslem vigilante group was behind the attack. "We're investigating the possibility that PAGAD is involved," he said. PAGAD declined to comment on the attack. Vigilantes from the group gained global notoriety in 1996 when its members lynched millionaire gang leader Rashaad Staggie, his slow death captured on video and film. Gang killings and revenge attacks by PAGAD have spiralled out of control in the last few years, particularly on the Cape Flats outside the city. But Woodstock, a suburb bordering on the city centre, has also seen a surge in shootings and petrol bombings at houses of alleged drug dealers over the past few months.