Doug Pizac/Invision/AP 1 / 9
Doug Pizac/Invision/AP 1 / 9

LOS ANGELES (AP) -- Janet, Randy and Rebbie Jackson say the executors of Michael Jackson's will are causing harm by damaging "fundamental family relationships" and isolating matriarch Katherine Jackson "from anyone questioning the validity of Michael's will."

RELATED: TJ Jackson Emerges as Katherine's Co-Guardian

The Jackson siblings released a statement late Friday through an attorney amid a fight over their brother's will with the executors of his estate.

RELATED: Paris Jackson Remembers Her Dad on Anniversary of his Death

On Thursday a judge named TJ Jackson, a cousin to Michael Jackson's three children, as co-guardian with Katherine Jackson, who was named their sole caretaker in the disputed will.

RELATED: Katherine Jackson Says She Was Kept From Communicating

Janet, Randy and Rebbie Jackson accuse the executors of a "relentless" negative media campaign. They say they plan to maintain their challenge and insist they're not motivated by money.

The executors did not immediately respond to calls or emails seeking comment.