It all began shortly after 3 a.m. Sunday on Admiral Wilson Boulevard near Rosemont Avenue in Pennsauken, New Jersey.
According to investigators, Victor Gutierrez ,31, was struck and killed by a white van.
The driver of that van, Ronale Thomas of Brockton Massachusetts, got out of the vehicle to check on Gutierrez, police say, but was hit by another car.
"He struck the pedestrian, never saw him then he got out to help and got hit himself," said Sgt. Christopher Sulzbach, Pennsauken Police.
The driver of that car fled the scene. Thomas survived but was seriously injured.
Pennsauken police say the only description of the striking vehicle they have, so far, is that it may be a silver 2002 to 2006 Ford Taurus or Mercury Sable.
Investigators say that clue came from a broken passenger-side mirror found at the scene.
Police need the public's help locating the vehicle and are urging the driver to come forward.
"We don't know why he fled the scene but we're pretty sure they knew. There was a lot of debris ahead of them on the roadway," said Sgt. Sulzbach.
Police have at least three witnesses at the scene.
An autopsy was conducted for Gutierrez but investigators are still trying to figure out why he was on that stretch of roadway.
Thomas is a driver for a company out of Massachusetts that subcontracts for the Red Cross.
"He was coming back from the Cape May area after delivering blood for the Red Cross and heading back up to Boston," said Sgt. Sulzbach.
Thomas remains at Cooper University Hospital. He suffered arm and head injuries, a broken leg, and he underwent surgery.
Police are hoping to interview him more on Monday.
Anyone with information is asked to call Pennsauken Police at 856-488-0080 x 2300.