Prince Jackson tweeted a screen grab of a group family message, which seems to reveal Janet didn't want the kids to see the 82-year-old guardian during her mysterious "disappearance" from their California home earlier this week.
It turned out Katherine was "resting up on the orders of a doctor" with her sons Randy and Jermaine in Arizona. Michael's daughter Paris Jackson tweeted on Thursday morning that her grandma had returned home.
The first part of the text Prince posted was sent to aunts Janet and Rebbie, demanding to see his grandma.
"This is enough so I am texting you for the simple fact that WE DEMAND TO SPEAK TO MY GRANDMA NOW," he wrote.
The screen grab shows Janet replied, "Please don't let them."
The screen grab was mysteriously deleted from Prince's Twitter account, but then re-posted, sparking questions about its validity.
The texts were sent on Monday — two days before a judge revoked Katherine's guardianship of the kids due to "intentional acts of third parties."
“Although I am happy my grandma was returned, after speaking with her I realized how misguided and how badly she was lied to. I'm really angry and hurt.
"For this whole time, they denied us contact to our grandmother," he continued.
"If you continue with your lies I will continue with the truth."
Tito Joe "TJ" Jackson, the son of Michael's brother Tito, has been appointed temporary caretaker of the kids. He now has access to funds from the late singer's $500m estate.
Paris meanwhile has claimed that her brother's tweets were for real, and that the posts were deleted by a hacker.