PHILADELPHIA (CBS) - Authorities are investigating a fatal police-involved shooting in West Philadelphia Thursday evening.

It happened a little before 7 p.m. in the 5600 block of Pemberton Street.

Authorities say while they were conducting a traffic stop, one of the three suspects in the vehicle fled, leading police in a foot chase westbound through an alley between Walton and Pemberton streets.

When officers caught up to the suspect, investigators say he and one of the officers got into a struggle. The suspect allegedly tried to reach for an officer's taser, prompting that officer to discharge his weapon three times.

The suspect was struck in the chest and pronounced dead at the scene.

Police are searching for the driver of the vehicle after he sped off some time during the pursuit. A third suspect was taken into custody.