You are right about the age, it's an oldie.
Well the movie isn't SUPPOSED to be funny ... but I do chuckle a hell-of-a-lot while watching it. The movie is fairly "underground", 'prolly 'coz it's not all that good.
If you wanna cheat:
Spoiler:
The movie is about a pedo who frames a retard for child molestation. Angry mob kills the retard - then the retard comes back for revenge with a potato sack on his head. .
If nobody gets it in a couple days, I'll spill the beans.
I was thinking of a scarecrow but couldn't think of any film titles...
Nobody wants to play with us Blinky!! where are all the horror posters.
My Bloody Valentine, original film for my guess Blinky, I doubt it though, can't remember that but one of the detectives reminds me of a character in My Bloody Valentine.