Trying to find the name of a movie with very little info to go on - help please?

This is a movie made in the 80s or very early 90s. I believe it is a sci-fi genre movie. When I was a kid I sneaked downstairs to watch the telly through the banisters before I was caught and promptly scared back to bed by an angry father! The only part I saw however, was a scene with a villain. He was an assassin of some sort, and his weapon of choice was a triple blade claw which he stabbed his victim with.I think the stabbing occurred in a dark smoky alleyway. A very cheery uplifting movie!! Of course as a young lad, this image left a rather lasting impression though I never did find out what the movie was... any ideas?