Police say a 21-year-old man was shot and killed in Philadelphia's Cedarbrook section Sunday afternoon just after speaking with a state House candidate about volunteering on his campaign.

The shooting occurred around 3:30 p.m. in the 1400 block of Vernon Road.

"Somebody walked up and deliberately shot someone with every intent of killing them," said Philadelphia Police Commissioner Richard Ross.

The victim was reportedly talking to Chris Rabb, an adjunct professor at Temple University's Fox School of Business, who is now a candidate for Pennsylvania state representative in the 200th District, when the suspect came up from behind and opened fire, hitting the man twice in the head. The suspect then fled the scene, heading south on Fayette Street.

Rabb "was talking to a voter, a nice young man who works the polls on election day," said Rabb campaign spokesman Chris Visco. "They were talking about the election. The young man was interested in Chris' campaign and his candidacy for the 200th."

Visco continued, saying that the victim died with a piece of campaign literature in his hand. He was initially supposed to be a poll worker for Tuesday's primary, but after speaking with Rabb outside a convenience store Sunday, he expressed interest in volunteering on the campaign.

The victim was pronounced dead at 3:48 p.m.

Police investigating the incident have more to worry about than just the initial shooting, however. Just four hours later, at 7:30 p.m., another man reported to be 18 years old was shot, while a 17-year-old was grazed by a bullet in a drive-by shooting. Both men were taken to the hospital where the 18-year old died and the 17-year-old is expected to survive.

Due to the time of the killing and the fact that it took place on the 8000 block of Temple Road - just around the corner from the first shooting - police believe this second shooting may be in retaliation to the first. Therefore, they're investigating the possibility of a gang rivalry being at play.

"I'm very frustrated by the fact that we were not able to prevent this second homicide," said Philadelphia Police commissioner Richard Ross. "We do believe that these are two rival factions. What they're fighting over we haven't pinned that down right now."

Police have yet to release the identities of the victims, and no arrests have been made in either shooting. The investigation is ongoing.

Anyone with information is encouraged to call the homicide unit at (215) 686-3334.