Video shows suspect shooting 77-year-old man in Juniata Park section of Philadelphia

PHILADELPHIA (WPVI) -- Chilling new video shows the execution of a 77-year-old man on his morning walk in Philadelphia's Juniata Park neighborhood.

Police released this video, hoping someone will recognize the suspect in a red

Loi Nguyen was shot and killed early Tuesday morning on the 4200 block of L Street.

The suspect runs up behind Nguyen and shoots him once in the back of the head, killing him.

Police say he's still on the run, and are looking for a motive.

Neighbors said the victim, identified as Loi Nguyen, was well-known and always exercised before sunrise.

They are also investigating if the same suspect was involved in an altercation with two other people a few blocks away an hour earlier.

Anyone with information is asked to call police at 215-686-TIPS.