JonBenet's Killer Found! After a six-month investigation, Radar can reveal a new bombshell in the Ramsey case.

Boulder lawmen blew any chance of bringing JonBenet Ramsey‘s killers to justice by making a shocking plea deal with a jailed sex pervert that keeps prosecutors from charging him with the six-year-old beauty queen’s murder.

Incredibly, law enforcement officials have been covering up their shameful blunder for two decades since the pageant princess was brutally molested, garroted and bashed with a baseball bat in her family’s Boulder, Colo., home on Dec. 25, 1996.

But after a six-month investigation, RadarOnline.com can now reveal JonBenet was killed by members of a twisted sex ring — and the key player outfoxed cops eager to solve OTHER crimes at any cost!

The pervert, whose name is being withheld at this time, is currently serving a 32-year sentence in Colorado’s Crowley County Correctional Facility for sexual assaults in 1993 and 1996. Cops had him in their crosshairs right after JonBenet’s murder. But he took himself out of the picture with a cunning plea bargain in other sex crimes that prohibits the authorities from testing his DNA to see if it matches male samples found in JonBenet’s underwear.

“Her killer may have protected himself from prosecution by going to jail!” a source told Radar. “At least one Ramsey investigator had this man’s name on his suspect list.”

Incredibly, one lawman wanted to follow up on him, but was told “to back off. The guy is protected by the plea deal,” a source told Radar.

Authorities have been protecting the monster, who is now about 50 years old, ever since in a shameful cover-up.

Radar learned that just weeks before the pint-size blonde died, the twisted creep entered a guilty plea to one count of sexual assault on a child, which resulted in 12 years of probation.

In May 2000, he violated probation and was sentenced to two and a half years behind bars. He was required to submit to DNA testing with Colorado authorities.

A few years later, during another sex assault trial, he made the plea bargain that put him away for three decades — but avoided the death penalty in the JonBenet case, which, chillingly, his ex-wife has said was one of his pet obsessions.

Authorities believe JonBenet was targeted by a pedophile ring and more than one person was involved.

They suspect the killers broke a basement window, crept into the house, slipped up to the bedroom where the girl was sleeping and knocked her out with a stun gun.

She was carried to the basement, bound, silenced with duct tape, molested, strangled with a garrote and smashed in the head with a baseball bat.

The jailed man also was known for binding his victims’ hands with rope or tape after breaking into their homes in the wee hours — and even owned a cattle prod or stun gun!

A set of footprints found at the crime scene were never identified, but investigators believe they could be linked to the kinky inmate. But since his DNA is off limits, there’s no justice for JonBenet.

“He wanted a total, encompassing deal where authorities couldn’t come back at him for his crimes,” legendary private investigator Bo Dietl told Radar.

“They do stupid deals like this all the time.”

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