Leonard Rowe told RadarOnline.com that investigators — commissioned by Michael’s younger brother Randy — proved a 2002 will the singer wrote is not valid because of a string of errors and a question over his whereabouts the date it was signed.

Rowe, Jackson's longtime friend and sometime financial advisor, revealed Janet chaired the recent roundtable at her Californian home

Investigators cited incorrect names of the pop star’s children and misspellings of second wife Debbie Rowe’s middle name, as key evidence.

“Michael would never misspell his children’s names -- especially on a document that important,” Rowe told RadarOnline.com, in an exclusive interview.

In the document, daughter Paris’ middle name is wrong. Lawyers had forgotten that part of her middle name was Michael -- Paris Michael Katherine Jackson.

Youngest son Blanket was listed by his nickname and middle name Joseph. His birth certificate names him as Prince Michael Jackson II.

Rowe said the investigation was spearheaded by Randy Jackson, himself and Brian Oxman, the Jackson family spokesman and attorney.

Family patriarch Joe Jackson -- who also is questioning the validity of his son’s will, which excluded him -- was not part of the investigation, Rowe said.

Rowe also revealed that Reverend Al Sharpton was prepared to come forward as a witness in their case.

Another explosive challenge to the will that named John Branca and John McClain as administrators of the superstar’s posthumous affairs is its signature date.

On the document, it shows Jackson signed it into effect on July 7, 2002.

However, Rowe said the pop star was in Los Angeles on that day.

The singer spent three days from July 6 to July 9 filing a petition against his record label executive Tommy Mottola in a long running court case with Sony music.

Rowe said Rev. Sharpton is willing to swear in an affidavit that he was with Jackson in New York on July 7.

“The whole world saw that Michael Jackson was in New York,” Rowe told RadarOnline.com.

“There’s footage of Michael with Rev. Sharpton on CNN.”

There are also hotel receipts to prove Jackson stayed in New York on July 7, Rowe added.

He said Jackson’s security team was also prepared to provide statements to prove his whereabouts at the time that the will was supposedly signed.

Last September, Los Angeles superior court Judge Mitchell Beckloff signed off on the papers, deeming it the most recent will.

The will named Jackson's 80-year-old mother Katherine as guardian of his three children and ordered that all his assets be moved into an entity known as the Michael Jackson Family Trust.

According to the document, Jackson's kids will receive 40 percent of their father's $300 million estate.

It also appointed as executors John Branca, a lawyer who began representing Jackson in 1980, and John McClain, a founder of Interscope Records.

“What would really solve a lot of questions about this will... there are three of four witnesses who are supposed to have witnessed the signing of the will,” Rowe said.

“I wish the estate would come forth with these witnesses.”

Rowe, no relation to Jackson's ex-wife, is releasing a tell-all book titled What Really Happened To Michael Jackson, to coincide with the one-year anniversary of Jackson’s death.

His allegations about Jackson’s death have been met with skepticism by some, who cite his time in prison after being convicted of wire fraud for his role in the cashing of a fraudulent insurance check.

But Rowe insists Jackson hired him to oversee his business and financial affairs during the scheduled London concert tour, This Is It.