A psychopath is slicing the heads off of victims in cars with a sword at a local drive-in and it's up to Detectives Larry and Mike(Bruce Kimball and Steve Vincent)to find out who it is. The drive-in theater was once a carnival and many of those who worked in it are employed. It could very well be the incredibly cranky, ornery, and all-around rude theater manager, Austin Johnson(Newton Naushaus)whose foul attitude stinks something rotten;once the barker, he has been left to take care of the entire business while his former employer sold the farm and ran off to Hawaii or some place. Another suspect is the "half-wit" janitor, Germy(Douglas Gudbye)who is an admitted former sword swallower, but seems too mild-mannered and simple-minded to be a killer. The main suspect is Orville(Norman Sherlock), a creepy peeping tom, spotted by Germy hanging around cars, spying on certain couples making out. The detectives attempt woefully to solve the case but their methods are a bit suspect(..why would you associate yourself with Germy, a possible suspect, no matter how nice and hospitable he might be?)..I mean two victims are killed in cars not feet from where they were staking out! The major problem established by a host of other users is the languid pace of the entire film. Some interrogation sequences are stretched too long and we witness the uncomfortable cast languishing with rather dire material. I did find the foul character of Johnson rather amusing in how he describes everyone he comes in contact with..never a kind word for anyone, he's quite the misanthrope. Johnson is the kind of character you yearn to see get stabbed in the throat with a sword. I also enjoyed the opening beheading..but director Seagall doesn't quite match this with the subsequent killings(..one victim's head falls off and a couple is skewered by the dreaded sword while hugging). There's a bizarre red herring set-up featuring the great Buck Flower chasing after a female victim(..actually played by his real daughter Verkina!) inside a warehouse with a machete(..he's considered a suspect, but anyone in their right mind knows that the film will ultimately end at the drive-in). The truly horrible climax at the end punctuates a rather ineptly made film..attempting to leave open the killer's identity, it only has you scratching your head. A plausible climax determining who between two obvious suspects might in fact be the real killer would've at least provided a satisfying conclusion to a rather poorly conceived horror film. The really oddball sequence where Larry and Mike are questioning Orville in his home(..with nude posters of models pinned all over his living room walls)really has to be seen to be believed..seeing Orville squirming and wallowing in misery over his sexual appetites(..he even admits out loud to "beating his meat" while at the drive-in, completely overwhelmed in embarrassment!)while the detectives appear quite appalled. A film like Drive-in Massacre only proved that in the 70's almost anyone could make a movie.