WASHINGTON (Reuters) - The U.S. Justice Department said Monday it has charged an Ohio man with acting as a “straw purchaser” of a gun used by a man accused of shooting and killing two police officers on Saturday.

Gerald A. Lawson III, 30, of Warrensville Heights, Ohio, was charged with aiding and abetting the possession of a firearm by a prohibited person, the department said.

An attorney for Lawson could not immediately be reached for comment.

His arrest on Monday came after two Westerville, Ohio police officers were shot to death on Saturday while responding to a domestic disturbance. The suspected shooter is a convicted felon who was prohibited from purchasing guns, the department said.The suspected shooter, Quentin L. Smith, is also in custody.

In a recording released by the authorities on Sunday, a woman who identified herself as Smith’s wife told a 911 emergency operator that her husband shot the two officers.

Officer Eric Joering, 39, died at the scene, and Officer Anthony Morelli, 54, died from his wounds at a hospital.

Both officers were shot when they entered an apartment in response to a 911 call that had hung up.

The Justice Department said Monday that an unnamed witness told them Smith gave Lawson the money to buy a Glock handgun he used in the shooting, plus an extra $100 on the side because he had a prior criminal record.

The department added that the two men have long been friends and were photographed together in pictures posted on social media accounts.

A firearms trace on the Glock also showed that Lawson bought the gun, the department added.

The incident prompted President Donald Trump to respond on Twitter over the weekend, saying he offered his prayers.

Attorney General Jeff Sessions also offered his condolences on Monday, in a speech he delivered to the National Sheriffs’ Association.