President Donald Trump’s former attorney says special counsel Robert Mueller raised the prospect of issuing a grand jury subpoena to compel the president to testify as part of the Russia probe.

Attorney John Dowd tells The Associated Press on Tuesday that Mueller’s team broached the subject in March during a meeting with Trump’s legal team. The meeting marks the first time the special counsel raised the possibility of compelling Trump to testify as part of the investigation into Russian election interference and possible coordination with Trump associates.

Mueller is also investigating the president for possible obstruction of justice.

Dowd’s comments come more than a month after he resigned from the legal team. Trump has since hired former New York City Mayor Rudy Giuliani and two former federal prosecutors to replace Dowd.