Marty Jannetty Claims Self-Defense In Bizarre Killing Confession

Marty Jannetty is now claiming self-defense in the apparent death of a man he says he killed 47 years ago ... saying he used a brick to fatally fend off a rapist.

The ex-pro wrestling star called in to the Boston Wrestling Sports show on Wednesday night -- where he was questioned about a bizarre Facebook post in which he suggests he killed a guy and dumped the body in the Chattahoochee River sometime around 1973.

At first, 60-year-old Jannetty tries to be careful about the language he uses ... but ultimately describes an incident involving a male bowling alley employee who allegedly tried to "rape" him in a car behind a building in Georgia.

"He was a front desk clerk," Jannetty said ... "He was known to sell the weed. What I didn't know was he lured in little kids."

Jannetty claims the man tried to grab his genitals, so Marty tried to flee ... but the man grabbed him by the hair and got physical with him so Marty couldn't escape.

That's when Marty says he grabbed a brick and fought back.

"I can't say he deserved to die, but he deserved to get his ass beat."

"And, when I was beating him in the head with a brick, I was only trying to beat his ass, I wasn't trying to kill him."

Jannetty suggests the man died -- and that's when he tried to get rid of the body.

"Can you imagine dragging a guy -- he's just tried to f*** you in the ass --- can you imagine dragging him to the river and throwing him in? And, then finding out on the news the dude's missing. You know the dude. And, you know more than that. That affected me bad, bro."

As we previously reported, the Columbus Police Dept. in Georgia has already opened a probe into the apparent killing.

In fact, a spokesperson from the homicide/cold case division told us, "The first step will be seeing if we have any missing persons or unidentified remains cases that match the limited information in the post."