Two Democratic members of Congress are asking the FBI to investigate a phone call last week during which President Donald Trump reportedly confronted Republican donor and billionaire casino magnate Sheldon Adelson about why he wasn’t doing more to boost his re-election campaign.

California Rep. Ted Lieu and New York Rep. Kathleen Rice, in a letter sent to the FBI on Monday, asked the federal agency to look into whether any crimes were committed during the course of the phone conversation between Trump and Adelson. According to Politico, which first reported the details of the call, Adelson reached out to Trump to talk about the coronavirus relief bill, but Trump turned the conversation to his campaign.

In the letter, Lieu and Rice allege that “a crime may have occurred” during the course of the call “depending on the details” of the conversation, as it is illegal for donors to ask elected officials to take action on legislation in exchange for money.

“In this case, Mr. Adelson discussed a specific piece of legislation, the Coronavirus relief bill, with the President,” they wrote. “In the same conversation, the President asked Mr. Adelson to do more to support his campaign. Depending on what exactly was said, a bribe or solicitation of a bribe may have occurred.”

The Politico article does not include any details that suggest that any action on legislation was asked for or promised in exchange for a campaign donation. However, the letter alleges that if Adelson “directly or indirectly promised anything of value to the President” in return for “a certain action,” it could “meet the elements of bribery.”

“We believe the public reporting has provided more than enough of a factual predicate to open an investigation into this matter,” they wrote. “We thank you in advance for your consideration of this request.”

The White House did not immediately respond to a request for comment Monday afternoon. A source close to Adelson dismissed the letter as “pure politics.”

According to Politico, Republican Party officials were primarily concerned that the call may have alienated Adelson, who is one of the party’s biggest donors. Adelson and his wife recently pumped $25 million into a super PAC supporting Senate Republicans and promised to spend $100 million on Trump’s re-election and other Republican causes in the run-up to the November election.

Read the letter below: