Michael Flynn, President Trump’s former national security adviser, was fired weeks ago, but his ties to Russia keep raising questions this White House won’t answer and dark suspicions it can’t seem to dispel.

Representative Jason Chaffetz, Republican chairman of the House Oversight and Government Reform Committee, and Elijah Cummings, the committee’s top Democrat, got right to the point on Tuesday, saying Mr. Flynn may have broken the law by failing to disclose payments totaling over $65,000 in 2015 from companies linked to Russia. They included $45,000 received from Russian state television for a speech in Moscow; on the same trip, he attended the network’s gala, sitting at the elbow of President Vladimir Putin. With his background, Mr. Flynn clearly knew that the failure to disclose payments on his security clearance forms could have disqualified him for a sensitive national security role.

Mr. Chaffetz also said Mr. Flynn, as a retired general and former director of the Defense Intelligence Agency, should have sought permission from the secretary of state and the secretary of the Army for his trip to Russia and for the payment. “I see no evidence that he actually did that,” Mr. Chaffetz said at a news conference on Capitol Hill.

Mr. Cummings said that the White House is stonewalling committee requests for documents related to Mr. Flynn’s hiring and firing, including records of his phone calls and correspondence. Mr. Chaffetz, amazingly, described the White House as “cooperative.” Sean Spicer, the White House press secretary, later called the committee’s records requests “outlandish” and “ridiculous.” Which can hardly be called cooperative.