New Hampshire state representative Al Baldasaro, who is also a Trump delegate from the state and has appeared with Trump at campaign events, made the comments on the Jeff Kuhner Show.
"I'm a veteran that went to Desert Shield, Desert Storm. I'm also a father who sent a son to war, to Iraq, as a Marine Corps helicopter avionics technician. Hillary Clinton to me is the Jane Fonda of the Vietnam," he said. "She is a disgrace for the lies that she told those mothers about their children that got killed over there in Benghazi. She dropped the ball on over 400 emails requesting back up security. Something's wrong there."
"This whole thing disgusts me, Hillary Clinton should be put in the firing line and shot for treason," he added.
Baldasaro has spoken at several Trump events, introducing Trump multiple times, including at an event in late May where he admonished the media for focusing on questions over Trump's donations to veteran's charities.
He later added in the radio interview that Clinton was a "piece of garbage."
A spokesperson for the Trump campaign did not immediately respond to a request for comment. The Boston Globe followed up with Baldasaro after BuzzFeed News' report and he said he stood by his comments.
Trump campaign spokesperson Hope Hicks told NH1 News, "We’re incredibly grateful for his support, but we don’t agree with his comments.”
As first reported by The Daily Beast, the Secret Service is investigating Baldasaro's comments.
“The U.S. Secret Service is aware of this matter and will conduct the appropriate investigation," a Secret Service spokesperson confirmed to BuzzFeed News.