officially withdrew himself from consideration for appointment as FBI director in a letter to President Donald Trump on Thursday.

Lieberman withdrew his name citing concerns about conflict of interest, the Wall Street Journal reports. These concerns stemmed from Lieberman’s work at the same law firm as Trump’s private lawyer Marc Kasowitz, whom the president recently retained to provide personal counsel on the on-going Russia investigations.

“I do believe it would be best to avoid any appearance of a conflict of interest, given my role as senior counsel in the law firm of which Marc is the senior partner,” Lieberman wrote in a letter Wednesday. He thanked Trump for the opportunity to discuss “the possibility of being nominated.”