Katherine Jackson's 'Disappearance'... Jermaine's Behind it Trent Claims

Katherine Jackson's sudden vanishing act while she's allegedly claiming elder abuse at the hands of nephew Trent Jackson is being masterminded by none other than Michael's brother Jermaine ... so claims Trent in new legal documents.

Katherine got a restraining order against Trent last month, claiming in a declaration he was pilfering cash and abusing her, something Trent vehemently denies.

Now Trent and his lawyer, Ron Rale, say they have serious doubts Katherine even wrote the declaration, and they're pointing the finger at Jermaine. They note Katherine says in the declaration she's been in London and therefore did not appear in court, but Trent thinks its something more sinister.

He points to a blow-up in 2012, when Katherine disappeared and went somewhere in Arizona. Trent claims Jermaine and some of M.J.'s other siblings essentially held her hostage, even taking away her iPad and cell phone and told her the TV was broken ... all in an effort to allegedly wrestle control away from Trent, who has been caring for Katherine since Michael died in 2009.

Trent and Rale believe history is now repeating itself and Katherine has again been stripped of her free will thanks to Jermaine and others, and it's all about controlling the M.J. Estate.