Dan Aykroyd -- Homicide Investigation Launched Over Crappy Movie

Who you gonna call? The police!

Dan Aykroyd became the focus of a homicide investigation when a landfill worker uncovered film of the actor standing over a bloody corpse -- and it turns out he's guilty ... of making a really bad movie.

Law enforcement officials in Calgary, Canada tell TMZ the dump worker found the damaged film on Wednesday afternoon, and turned it in to police ... thinking he had stumbled upon evidence in a murder.

We're told the employee didn't recognize Aykroyd, but once investigators cleaned the dirty negative they spotted the ghostbuster. Problem is ... they couldn't tell which one of his nearly 100 flicks they were seeing.

Police then contacted All American Speakers -- a company that books celebs for events -- and also Dan's reps ... who revealed the scene was from the 1990 bomb "Loose Cannons."

If you've never heard of it ... that's cool with Dan. When we called about the investigation he told us, "The movie should have been left in the landfill where it belongs."

Case closed.