Communities must provide more information to police to stop "evil" prevailing and help combat organised crime, Justice Secretary Kenny MacAskill said.
Mr MacAskill said gangsters and criminals were no longer untouchable but could be if the public did not call police.
The plea follows the death of Kevin Carroll, 29, who was shot dead in an apparent gangland execution while he sat in the back of an Audi car outside an Asda store in Robroyston, Glasgow, last Wednesday.