KISS Guitarist Ace Frehley Cause of Death Released

Legendary KISS guitarist Ace Frehley passed away Thursday, Oct. 16, after his family made the difficult decision to turn off his ventilator ... and today his cause of death has been released, TMZ has learned.

TMZ confirms, Ace died as a result of blunt trauma to the head due to a fall.

According to the Morris County, New Jersey Medical Examiner's report ... Ace suffered a fracture to the back of his skull, a subdural hematoma -- a collection of blood formed between the brain's protective outer layer and the brain itself -- and a stroke. His manner of death was ruled an accident.

The 74-year-old musician was put on life support after a nasty fall in a studio led to a brain bleed. According to the report, he underwent a procedure to evacuate the subdural hematoma, but to no avail.

Ace was a founding member of KISS ... joining forces with Gene Simmons, Paul Stanley, and Peter Criss. He shredded guitar with the band from 1973 to 1982 ... but left the group amid substance abuse issues and creative differences.

Back in March this year, Ace was all smiles talking about his comeback following a nasty arm injury ... in an interview with New Jersey newspaper The Aquarian, he said, "I just spoke to a psychic. She goes, 'Ace, you’re going to live to be a hundred.' So I said, 'No problem!'"

He's the first original member of KISS to die.