"She is a disgrace for any, the lies she told those mothers about their children that got killed over there in Benghazi," he said on the Jeff Kuhner Show Tuesday. "She dropped the ball on over 400 emails requesting back up security. Something's wrong there."
"Hillary Clinton should be put in the firing line and shot for treason," he continued.
His comments about Clinton were first reported by Buzzfeed.
The House Select Committee on Benghazi, in its final report, criticized the State Department for the lack of adequate security at the consulate ahead of the 2012 attack, but did not find that Clinton was personally responsible for making security decisions. The Clinton camp called the report a "partisan sham."
Asked about Baldasaro's comments, Secret Service spokesman Robert Hoback said the agency is "aware of this matter and will conduct the appropriate investigation."
Baldasaro did not immediately return a request from ABC News for comment.
Clinton Communications Director Jen Palmieri said in a statement: "Donald Trump's overtaking of the Republican party – and his constant escalation of outrageous rhetoric – is in danger of mainstreaming the kind of hatred that has long been relegated to the fringes of American politics where it belongs. This week at the Republican convention, we've seen the clearest embodiment yet of this dangerous phenomenon."