A nonpartisan government watchdog is calling for a federal investigation into Massachusetts Congressman and U.S. Senate candidate Seth Moulton after he was caught on camera allegedly hitting the phone out of a person’s hand who had asked him if he would endorse controversial Maine U.S. Senate candidate Graham Platner.

The Center to Advance Security in America (CASA) sent a letter to U.S. Attorney Leah Foley requesting her office investigate the sitting congressman for the physical attack on the still unnamed person, citing potential violations of state and federal law.

“We write to respectfully request that the United States Attorney’s Office for the District of Massachusetts initiate an investigation into potential violations of federal and/or state criminal laws by Seth Moulton, a member of the United States House of Representatives, for his recent physical attack on a political reporter with an opposing viewpoint while entering his campaign office,” CASA Director James Fitzpatrick wrote in a letter to the U.S. Attorney’s Office, dated June 25.

“Here, a full investigation into Representative Moulton’s intention, motivation, and desired outcome of his conduct against this political reporter is warranted. Moulton’s aggression should be called out for what it is — political violence. Based solely on a routine question regarding candidate endorsement, and with the political reporter not moving toward Moulton but instead Moulton moving toward the reporter, Moulton became “pisse[d]” and struck at least the reporter’s phone,” he said.