BISMARCK, N.D. — U.S. Sen. Heidi Heitkamp wants a special prosecutor to investigate possible ties between President Donald Trump and Russia following the president’s firing of FBI Director James Comey.

The North Dakota Democrat says Comey’s firing “raises far more questions than it answers.”

Republican Sen. John Hoeven says the case has been made for Trump to fire Comey but the timing raises questions. He’s calling for a continued investigation by a bipartisan Senate committee into last year’s presidential election, “including any Russian interference.”

GOP Rep. Kevin Cramer did not immediately respond to messages seeking comment.

Comey traveled to North Dakota last year to open a FBI office in Williston and to visit with tribal officials at the Fort Berthold Reservation.