A federal judge has confirmed that a former business associate of President Trump helped the U.S. government track down Osama bin Laden, Politico reports. Judge I. Leo Glasser said Thursday that Felix Sater—who spearheaded negotiations for Trump Tower Moscow during the 2016 election, a role that has now led to the media shedding light on his past—did “very interesting and dangerous things” throughout his 10 years as an FBI informant. “He co-operated,” Glasser said at a hearing in the Eastern District of New York to address a lawsuit filed by First Look Media, which hopes to unseal records regarding Sater’s involvement with the government on a number of national-security issues. “And you know what he did over the 10, 11 years, because you told me that you know. He provided the telephone number of Osama bin Laden. He has done an awful lot of very interesting and dangerous things.”