A 21-year-old man has been shot and killed in Philadelphia while talking to a candidate for the Pennsylvania House.

Police say the unidentified man was shot Sunday afternoon while speaking to Democratic candidate Chris Rabb about the state's upcoming primary. Police say the gunman shot the victim twice in the head. He was pronounced dead at the scene.

A spokesman for Rabb's campaign says the victim told Rabb that he was planning to work the polls on Tuesday. The man also expressed interest in volunteering for Rabb's campaign.

Rabb is running for a seat in the 200th District, and was canvassing the area at the time. He was not hurt.

Police say the gunman fled on foot. A motive for the shooting remains unclear. No arrests have been made.