WASHINGTON // Somewhere, deep in the archives of the CIA, there may or may not lie blueprints for the world's most classified vacuum cleaner.
Confined to the basement of a CIA secret prison in Romania about a decade ago, the admitted mastermind of the September 11 attacks, Khalid Sheikh Mohammed, was getting bored. He asked his jailers whether he could embark on an unusual project: Mohammed, who had earned his bachelor's degree in mechanical engineering, wanted to design a vacuum.
The agency officer in charge of the prison called CIA headquarters and a manager approved the request, said a former senior CIA official.
Mohammed had endured the most brutal of the CIA's interrogation methods and had confessed to a career of atrocities. But the agency had no long-term plan for him. Someday, he might prove useful or even stand trial.
"We didn't want them to go nuts," the official said. He was one of several who spoke on condition of anonymity.
So, using schematics from the internet as his guide, Mohammed began re-engineering one of the most mundane of household appliances. The result is but one peculiar, lasting byproduct of the controversial US detention and interrogation programme.
By the CIA's own account, the programme's methods were "designed to psychologically dislocate" people. But once interrogations stopped, the agency had to try to undo the psychological damage inflicted on the detainees.
After the CIA prison in Poland was closed in September 2003, Mohammed was moved to a secret site in Bucharest.
The prison had a debriefing room, where Mohammed, who saw himself as something of a professor, held what he called "office hours". While chained to the floor, he would lecture the CIA officers on his path to militancy, his childhood and family. Tea and cookies were served.
Along with the other five detainees at the prison in Bucharest, Mohammed was given "homework" assignments about his knowledge of Al Qaeda. He was given Snickers candy bars as rewards.
Mohammed was also given books, former officials said, and enjoyed the Harry Potter series.
Mohammed graduated from North Carolina A&T State University in 1986. It is not clear why Mohammed was interested in designing a better vacuum, and it remains a mystery how far he got with his designs. The prison in Romania was shut in 2006 and Mohammed was transferred to Guantanamo Bay, where he remains.
It is unlikely he was able to take his appliance plans to Cuba.
Mohammed's military lawyer, Jason Wright, said he was prohibited from discussing his client's interest in vacuums.
"It sounds ridiculous, but answering this question, or confirming or denying the very existence of a vacuum cleaner design … would apparently expose the US government and its citizens to exceptionally grave danger," he said.