PITTSBURGH -- There is new information about the fatal shooting of State Trooper Joseph Pokorny.

Police said Jabbar James, 28, and Phillip Peterson, 30, were brought into police headquarters for questioning Tuesday night.

They have since been released.

Two people who were brought in early Wednesday were then brought back to police headquarters.

Both were brought in from jail where one individual was being held on a parole violation.

They are in police custody Wednesday night but no charges have been announced.

Police are still searching for Jack Woods.

Police believe Woods may have valuable information about the shooting.

They are being careful not to call him a suspect at this time.

Wood's mother, Yolanda Thompson, is making a plea for her son to turn himself in to police.

She said she is worried something might happen to Woods.

She said he has nothing to do with the shooting but wants him to come forward and clear his name.

Thompson said, "I am waiting for him to contact me so I can ask him to turn himself in because I don't want anything to happen to him.

I was upset because I know that is not a part of Jack.

Family members said he was released from a halfway house two months ago.