John Carpenter -- the attorney repping Wade Robson and James Safechuck -- tells TMZ ... "The Los Angeles Police Department and Santa Barbara Police Department gave Michael Jackson and their legal team including Thomas Mesereau all of the incriminating evidence showing that Michael Jackson was sexually abusing children and that his corporations knew about it."

John claims Michael Jackson's companies have had this evidence for decades -- and so he believes they're entitled to the same information.

He adds ... "I understand why the Michael Jackson defense team doesn’t want us to have it."

Thomas Mesereau and Jennifer Keller -- the attorneys representing Michael Jackson's corporations -- have hit back at John's claims, slamming them as false. They say Wade and James' team have the same information they have ... insisting there is no credible evidence proving MJ ever inflicted abuse on them as children. They also say their legal endeavors over the years on this front have yielded nothing of substance.

They tell TMZ ... "This was confirmed by Mr. Jackson’s lengthy criminal trial in 2005, where he was acquitted 14 times and completely exonerated by a very conservative jury. This is a desperate attempt by Robson, Safechuck, and their attorneys to poison the jury pool and to promote their uncorroborated allegations against Michael Jackson. This case should be tried in a court of law, not in the media."

These competing statements come on the heels of MJ's production company trying to block Wade and James' team from accessing his criminal file ... claiming the accusers were fishing for shots of the King of Pop's junk.

As we previously reported ... Wade and James have both alleged MJ molested them as children -- and are finally getting their day in court. As part of their revived lawsuit, the men's legal time tried to subpoena docs from MJ's police file -- which may include photos of Michael's naked body from his '93 child molestation investigation.