... aka: Harder They Fall, The
In a small theater, some (awful!) actors are rehearsing for an upcoming performance of "The Taming of the Shrew." Little do they know, but their lead actress Ann Johnson ("June Medusa" / Maggie Williams) has just been raped and strangled to death right upstairs. A similar fate befell another actress at another theater just two weeks earlier. Hoping to crack the case, and having already had some prior acting training in college, mustachioed detective Winston Rains (Kirt Jones) comes up with a plan to join the theater troupe in hopes of trapping the grunting, heavy-breathing psycho. He almost immediately finds himself in a sexual relationship with actress Julie (Cindy Johnson) but when she discovers his gun belt hidden behind a pillow she's a little upset ("You're a lying pig, you fucking bastard!") and politely asks him to leave ("Get the fuck outta my house!") The psycho then stops by, bends her over, rapes her in front of the fireplace and then strangles her.
Julie somehow manages to survive the attack. Instead of going to the police like any other human being with an IQ above 70 would, she shows up at the theater the next day looking to tell Winston what happened. However, she doesn't get the opportunity and, once she gets back to her apartment, the psycho's there waiting on her. After forcing her to perform oral sex on him, he strangles her again... and makes sure he finishes the job this time! By the way, all of the women in this movie do absolutely nothing to stave off the sexual attacks of the psycho other than squirm and look mildly uncomfortable and seem to go down on any male anywhere at any time who's within spitting (or swallowing) distance. That leads the detective to getting involved with yet another actress named Marie ("Sharon Sharalik" / Nina Fause), who becomes the next target.
It's clear that the killer is someone who's working on the Shakespeare production and the suspect roster includes theater director Andy (Peter Puluva) and bitter, washed up former Broadway star Cliff ("Mel Vickson" / Keith Erickson). It's also clear that the director had seen Mario Bava's Blood and Black Lace as the psycho here wears a nearly identical get-up that includes an all-black outfit, a wide-rimmed hat and a tight, expressionless mask. Yet it's not an unmasking that uncovers the identity of the killer but comparison of another body part that the psycho constantly has dangling out of his pants.
This is more or less a terrible regional theater production of The Phantom of the Opera as a hardcore porn. Thankfully, it's awful in a pretty entertaining way, at least as far as the terrible acting, laughably bad dialogue and pitiful attempts at action and horror are concerned. Of course to get to the funnier moments first requires you to sit through (or if you're me, fast-forwarding through) lots of boring, unflatteringly photographed 70s sex that's shoehorned in at every given opportunity. And even that's presented in a rather bizarre fashion. You can tell that some of the actors were willing to do the sex while others were not. As a result, most of the sex seems to have been shot as softcore but with hardcore close-ups (possibly using doubles) added later on. About half of the sex is technically rape, though these scenes aren't the least bit believable or disturbing due to the lack of resistance and emotion from the actresses.
This has been released numerous times by numerous labels in recent years. It was part of a 2005 box set released by Alpha Blue Archives called "The Roughies: Cum Crimes," was part of a "Rapist Rampage" double feature (along with the slightly better-known Wet Wilderness) by After Hours Cinema released in 2008 and was one of twelve films included in Vinegar Syndrome's "All Night at the Bizarre Art Theatre Collection" set released in 2016. I skimmed through several of these releases and none of them had opening or closing credits or even as much as a title card!