Senate Homeland Security Committee Chairman Ron Johnson (R-WI) signaled Wednesday that he will request Obama administration officials, including former Vice President Joe Biden, to testify in the wake of revelations that they may have sought to “unmask” communications by retired Army Lieutenant General Michael Flynn.

“Right now we’re in the information-gathering phase of this and this obviously, from my standpoint, raises a lot more questions than it actually answers,” Johnson told reporters, according to The Hill. “We will start requesting interviews with those individuals.”

“I want to find out what you were looking at, why you unmasked an American’s identity and how you used that,” the Wisconsin Republican added, before noting that he will seek interviews with former Director of National Intelligence Clapper, former CIA Director Brennan, Obama Chief of Staff Denis McDonough, and “possibly the vice president.”

Johnson’s remarks come after acting Director of National Intelligence Richard Grenell submitted a declassified list to the Wisconsin Republican and Sen. Chuck Grassley (I-IA) of Obama administration officials who had requested names to be “unmasked” between November 8, 2016, and Jan. 31, 2017.