Donald Trump ’s pick to be FBI director, Christopher Wray, was at the center of a controversial immigrant detentions in the immediate wake of 9/11, when dozens of Muslims were spirited away to maximum security prisons and kept from communicating with their families and lawyers––sometimes for weeks.

Washington D.C. On September 11, 2001, Wray was working in the Deputy Attorney General’s office in downtownAfter the attacks, government lawyers rushed to find what steps they could take to try to forestall any other potential attacks.

One of the most controversial moves was by the Immigration and Naturalization Service (a now-defunct agency whose responsibilities were passed on to the Department of Homeland Security). The INS detained more than 700 people who the FBI suspected could have been linked to the 9/11 attacks.

According to the watchdog report, issued by the Justice Department’s inspector general in April 2003, almost all were men, mostly from Pakistan, Egypt, Turkey, Jordan, India, and Yemen. They had all committed some sort of immigration violation, either staying longer than their visas allowed or entering the U.S. illegally.

That report noted that if those men had been arrested just because of the immigration violations, they either wouldn’t have been detained at all or would have been put in immigrant detention centers with access to visitors and attorneys. Instead, though, they were put in maximum security prisons and, at first, couldn’t communicate with their family or lawyers. It was a “communications blackout,” according to the report. The detainees’ families and lawyers didn’t know where they were or why they had been locked up.

And that’s how Wray wanted it. The director of the Bureau of Prisons, Kathy Hawk Sawyer, told investigators that Wray and his colleagues directed her to restrict the detainees’ communication as much as was legal.

With that blessing, Bureau of Prisons officials kept the detainees from having any communication with the outside world. Some of the detainees were in the communications blackout for weeks, unable to talk to their families or lawyers, even by sending or receiving letters.

Officials with the Bureau of Prisons told the inspector general that they did let detainees send mail so their families could know where they were being held.