EXCLUSIVE INTERVIEW: 'My Wife Was Raped, Robbed & Murdered', Says America's Got Talent Contestant

The mother-of-three vanished while her rocker husband was waiting in line to audition for the hit NBC show.

Her body, clad in just her underwear, was found at about 8 a.m. and investigators initially believed she'd plunged eight stories to her death.

Joe, a singer/guitarist who went ahead with his audition in front of judges Piers Morgan, Sharon Osbourne and Howie Mandel, said he learned of his wife's death when police showed him a graphic photo.

"I believe she was strangled," he said. "As soon as I saw the photo, I said, 'Someone strangled my wife' because I could tell, from looking at her.

"I kissed her on the lips on the piece of paper and then they took it from me."

Joe also revealed Laura was found without three expensive diamond rings when she was discovered.

"She was wearing three expensive solitaire diamond rings all stacked on one finger and those rings were missing, I believe stolen, when she was found," said Joe.

"But I don't believe that was the motive, I believe the motive was rape and she was fighting to save her life. This was a rape that went too far."

In a case that has baffled Hollywood, Joe said he has been forced to launch his own investigation and has employed private investigators to find out how his wife of 26 years died, because "police are not telling us anything."

Cops believe the case is a tragic accident, but unconvinced, the musician has offered a $25,000 reward for information leading to the arrest of the perpetrator.

"It's impossible that she fell down the stairs or over a railing," Joe told RadarOnline.com.

"One, Laura would not be using the staircase if there was an elevator right there, and two, if you fall over a rail you're going to the bottom, not ending up on another floor.

"Thirdly, one thousand deaths a year are caused by falling down stairs and the highest percent of that are elderly people. You know what percentage that put this case in; you don't have to do the math to figure it out."

Joe - who described himself as a "broken man with a family that is suffering hour-by-hour" - also accused cops of destroying the crime scene at the historic downtown Los Angeles hotel, where he and Laura had been staying after celebrating his AGT try-out.

"The police were wasting precious time and destroying a crime scene by allowing loads of people access the hotel," he said.

"They should have closed the hotel down and disallowed anyone from leaving the hotel."

Instead, Joe added, even his own son was able to collect his mother's belongings from their room, while the hotel continued to operate as normal.

"My son and nephew walked out with clothes we were wearing the night before," Joe said.

"I pray every day that the investigators haven't botched this and they're just not saying anything because they have not come up with a solution as to what happened to Laura."

Joe, who was named a person of interest in the death, said cops interrogated him for nearly seven hours, all while he was handcuffed to a chair and wearing nothing but underwear.

"The police made me strip down because they were looking for scratches on my body, probably looking for marks that could have indicated there was some sort of struggle," Joe said.

"There wasn't any... God knows how many hours I was stripped down to my underwear, handcuffed to a f**king chair, in pain and screaming for help, to have the cuffs loosened.

"If I am a person of interest, I am ok with that given it is a general rule of thumb in investigations like these. However, all this time, the killer is still out there.

"I was even threatened by the police if I was seen on surveillance video that I could do 20-years-to-life and my response was:'f**k you'."

Joe said his offer of a polygraph was rejected.

He added, "I'm tired of it...it is not our style to remain silent. Laura and I fought for what we believe in. I just wish someone would look into this as I am spending my life savings on trying to figure out what happened to my wife."