British ex-spy Christopher Steele declined to give an interview to U.S. Attorney John Durham’s team for its review of the Russia investigation.

Representatives for Steele, whose unverified dossier was used by the FBI to obtain warrants to wiretap a member of President Trump’s 2016 campaign, were recently approached by members of the federal prosecutor’s team, and they said the former MI6 agent would not cooperate with the inquiry, according to Reuters.