How the self-described former chief of al-Qaida operations reddened his beard for his May arraignment and again at last week’s hearing had been a five-month mystery.

His lawyers are under a prison camp gag order and the detention center is especially secretive about what goes on in Camp 7, Guantanamo’s clandestine prison for former CIA captives.

Tuesday, Army Lt. Col. Todd Breasseale said in response to a five-month-old question that Mohammed “did craft his own natural means” inside the prison camps to concoct his self-styled beard dye.

“I don’t have his exact procedure,” Breasseale said, “but can confirm the use of at least berries and juice to create a kind of harmless dye.”

Mohammed got to Guantanamo in 2006 after 183 rounds of CIA water boarding and boasted that he planned the attacks of Sept. 11, 2001, “from A to Z.” He and four alleged accomplices face a death penalty prosecution as organizers, funders and trainers of the 9/11 hijackers.

At his hearing last week, Mohammed got permission from his judge, Army Col. James L. Pohl, to wear a hunting vest to his trial. The prison camps commander had vetoed the attire.

The 49-year-old, U.S.-educated Pakistani has come to court carefully adorned — in a white turban and traditional tunic — a sharp contrast to his disheveled appearance in a photograph taken at his 2003 capture, which showed him rousted from bed in an ill-fitting T-shirt with black stubble on his chin.

The next time Mohammed was seen in public, at a 2008 war court hearing, he had a massive gray and white beard that made him look like an old man. Author Terry McDermott, who co-wrote a book about Mohammed, “The Hunt for KSM,” said the dye reflected a certain narcissism.

“It’s all vanity,” he said. “Remember, this is the guy who likened himself to George Washington.”