Protesters demonstrated Friday for a third day over the fatal police shooting in Pennsylvania of an unarmed black teen fleeing a traffic stop as they sought to get the attention of a nation engrossed by the immigration debate, and to pressure officials to charge the officer.

Hundreds of marchers chanting "Who did this? The police did this" shut down a Pittsburgh area highway in the early morning hours, and a small group staged a sit-in outside the district attorney's office later in the day.

Demands for answers to why a police officer shot 17-year-old Antwon Rose Jr. seconds after he bolted from a car grew with an emotional speech by state Rep. Jake Wheatley at the state Capitol, and a videotaped appeal by the legislator and two other black Pittsburgh area lawmakers for a "thorough and transparent investigation that builds community."

"My heart is heavy right now," Wheatley said , decrying both Rose's death and the street violence that earlier in the week left a young rapper dead. "We cannot casually keep closing our eyes and ears to the fact there's a group of people whose lives seemingly don't matter."

Rose was shot Tuesday night in East Pittsburgh, a suburb of Pittsburgh, after the car he was riding in was pulled over by Officer Michael Rosfeld because it matched the description of a car wanted in a shooting in a nearby town, police said. The car had bullet damage to a back window.

As Rosfeld was taking the driver into custody, a video taken from a nearby house shows Rose and a second passenger running from the car. Three gunshots can be heard, and the passengers can be seen either falling or crouching as they pass between houses. It is unclear from the video if Rosfeld yelled for them to stop.