Prosecutors in the Natalee Holloway case are investigating the chilling possibility that a renegade cop may have helped dispose of the 18-year-old honor student’s body, The National Enquirer has learned.

And, as prime suspect Joran Van der Sloot enjoys freedom in Holland, it fuels fears that the case against him and two other suspects in Aruba has been successfully sabotaged. “There are powerful people on the island who don’t want this case solved,” said a close source.

And American investigator Arthur Wood, a retired U.S. Secret Service agent, said bitterly: “There’s no doubt in my mind that the case has been sabotaged from within.

“Soon after Natalee went missing on May 30, one of the top detectives on the case told me he had a reliable lead that she was being held in a certain house — and asked me to do surveillance there. I was puzzled and I told him, ‘Surely that’s a job for the police.’ He looked me in the eye and said, ‘I can’t trust my own officers.'” When Wood searched the house, he found nothing.

Joran, 18, and his pals Deepak and Satish Kalpoe were released from prison in early September — despite remaining under suspicion of rape and murder. Two days later Joran an was allowed to fly to Holland and enroll in college in Arnhem.

Meanwhile in Aruba, the possibility that a cop may have been involved in Natalee’s disappearance has been a well-kept secret until now.

Wood, who’s been on the island since June, said: “It began with a witness who was at the lighthouse area on the beach shortly before a big search for Natalee’s body was about to start there. In the distance he saw a police car on the dunes with its trunk open. When the witness got closer, the man slammed down the trunk and took off.

“Some time later a woman came forward. She said she’d been told that a policeman helped to dig up Natalee’s body from the sand at the lighthouse where it had been hidden.

“Everyone agrees that if the body was dumped at sea, as detectives believe, the killers must have had some cool-headed professional help. The cop could have provided that.”

“I believe the cover-up began from the start. The police commissioner then in charge of the case was an old friend of Joran’s father Paulus — and sources claim he was overheard agonizing over the case.'”

“Even Natalee’s mother Beth Twitty found evidence of a cover-up. She gave a statement to police, which she was told had to be typed in Dutch before she signed it. Weeks later she had someone translate the document she had signed — and was shocked to find some things were totally different from what she’d told police.

“Significantly, details about her conversations with Joran and the Kalpoes had been changed — to the benefit of the boys.”

Joran’s flight to Holland has only deepened the grief of Natalee’s mother, who turned detective to find much of the evidence that put Joran behind bars.

Said an insider: “When he was released, Beth cried all night. But she won’t give up. She said ‘I’m going to make sure Natalee’s voice will never be silenced.’ ”