House Oversight Committee Chair Jason Chaffetz (R-UT) on Tuesday said that he is ready to issue a subpoena for a memo that fired FBI Director James Comey reportedly wrote documenting a request President Donald Trump made for him to shut down his bureau’s investigation into former National Security Adviser Michael Flynn.

Chaffetz tweeted that his panel “is going to get the Comey memo, if it exists.”

“I need to see it sooner rather than later,” he said. “I have my subpoena pen ready.”

.@GOPoversight is going to get the Comey memo, if it exists. I need to see it sooner rather than later. I have my subpoena pen ready. — Jason Chaffetz (@jasoninthehouse) May 16, 2017

In a letter to acting FBI Director Andrew McCabe later Tuesday evening, Chaffetz requested “all memoranda, notes, summaries, and recordings referring or relating to any communications” between Trump and Comey.