A convicted jihadist serving a life sentence in federal prison as the “20th hijacker” in the September 11, 2001, attacks on the U.S. homeland has reportedly offered to testify during the 9/11 trial to “expose the Saudi Royal double game with” the late al-Qaeda leader Osama bin Laden.

His offer comes as hundreds of families have filed a lawsuit that, unlike others, contains a detailed account of Saudi Arabia’s role in the 9/11 attacks.

“I am willing to fully testify on the 9/11 case, even if I was charge on the death penalty case as it incriminate me,” Zacarias Moussaoui, self-identified as “Slave of Allah,” said in broken English in a hand-written letter.

“My take is he would like to be in the spotlight and is bored in solitary,” Edward MacMahon, the terrorist’s former defense attorney told the Miami Herald.

In response to his allegations, the Saudi Embassy has labeled the French-born U.S. prisoner as a “deranged criminal.”

Besides “Slave of Allah,” he also signs his filings as an “Enemy Combatant,” which he reportedly is not.

Currently, the 48-year-old Moussaoui is serving life behind bars at the SuperMax prison in Florence, Colorado.

The jihadist pleaded guilty in federal court to six 9/11 attacks-linked conspiracy charges in 2005.

According to the Pentagon’s war court website, Moussaoui has written at least three times to Army Col. James L. Pohl handling the September 11 mass-murder case, which still has no trial date.

Judge Pohl has not confirmed receiving the terrorist’s letter, noted the Herald.

“One of his defense lawyers, Gerald Zerkin, described Moussaoui as ‘a compulsive letter writer’ who sent perhaps 300 letters to U.S. District Court Judge Leonie Brinkema, who handled his trial,” adds the Miami Herald.

Moussaoui’s request for an opportunity to expose the Sunni Saudi kingdom’s ties to bin Laden comes as a new lawsuit has surfaced claiming the Saudis provided material support to al-Qaeda, a claim to which the jihadist is no stranger.

The lawsuit claims the Saudi kingdom enabled al-Qaeda to kill the estimated 3,000 people on American soil on 9/11.

New York Daily News reports:

The Manhattan Federal Court lawsuit, filed Monday by more than 800 victims’ families, provides extensive accusations about the Gulf nation’s complicity — such as by bankrolling the attack. Saudi Arabia “actively supported al Qaeda in its final preparations for the September 11th attacks,” court papers contend. And the country did so “through a network of the kingdom’s officers, employees and/or agents who met with and aided the hijackers, providing them with money, cover, advice, contacts, transportation, assistance with language and U.S. culture, identification, access to pilot training and other material support and resources,” the suit charges.

In the latest letter sent to the military judge presiding over the 9/11 attacks, dated January 29, 2016, the imprisoned jihadist offers to testify about the “real” mastermind behind the attacks.

He then names “Saudi Prince Turki, Princess Haifa, and a man identified only as Omar,” the lightly redacted letter shows.

The U.S. has identified Khalid Sheikh Mohammed (KSM), who is awaiting a death penalty tribunal as the mastermind of the September 11 plot.

Moussaoui “is just one of several men described as the missing ‘20th hijacker’ in the Sept. 11, 2001 attacks that killed nearly 3,000 people in New York, at the Pentagon and in a Pennsylvania field,” reports the Miami Herald.