For the first time Thursday, KING 5 News learned that other adults may be involved in Marc Gilbert's videotaped sex crimes.

That's just part of the new evidence prosecutors were forced to unveil to ensure Marc Gilbert stays in jail.

Gilbert's attorney filed a new motion to try to get him out of jail citing weak and faulty evidence.

But Thursday, federal prosecutors in Seattle fired back. They took the wraps off much of their case, filing with the court an FBI report, search warrant evidence, and detailed statements from young victims.

It's the crux of the case against wealthy Pierce County pilot Marc Gilbert, arrested late last year and accused of molesting boys since the 1980's.

This previously confidential FBI report shows why authorities wonder if other adults could have been involved.

Agents say one victim told them "Gilbert has allowed and arranged for a man named 'Jerry' to spank (the victim) on several occasions. The victim was very angry at Gilbert for introducing him to Jerry. Jerry spanked the victim across his lap with both his bare hand and a paddle."

"He told me to take down my pants and he had me lay on his lap, and he would spank me with a wooden spoon," said alleged victim Joseph Mack, who is one of several young men who came forward after Gilbert was arrested.

The pilot allegedly offered boys flying lessons and at his Lake Tapps home and at another in Chelan, plied them with alcohol.

Federal prosecutors told the court that agents have now interviewed several dozen boys, many of whom have confirmed the defendant sexually abused them.

They say they've identified 107 scenes on home video where Gilbert spanks, paddles, whips and canes underage boys.

Prosecutors say the tapes show carefully orchestrated scenes in which Gilbert orders the boys to strip and then plays the role of a strict teacher.

"Whatever answers I got wrong, questions he would ask me, he would - you know - be a spanking," said Mack.

That law enforcement source says after Gilbert's case became public, at least one man came forward, apparently concerned that he might be on one of the videos.

So far though Gilbert is the only one charged.

We were unable to reach his attorney for a response to all this new evidence released by prosecutors.