PHILADELPHIA (WPVI) -- A 16-year-old bystander who was shot in the head while waiting for a SEPTA train at the 15 Street Station last week has died.
Tyshaun Welles was shot around 9:30 p.m. last Thursday on the westbound SEPTA platform at the 15th Street Station at 15th and Market streets in Center City Philadelphia.
He was taken to Thomas Jefferson Hospital in critical condition but died on Tuesday.
The Philadelphia District Attorney's Office approved charges Friday against two teenagers involved in the SEPTA shooting. Both are being charged as adults and both have a criminal history.
Quadir Humphrey, 18, and Zaire Wilson, 16, are facing charges of aggravated assault, simple assault, conspiracy and other related offenses.
Sources said the DA is now working to upgrade those charges.
Investigators believe the shooting stemmed from a disturbance involving a large group of juveniles on the SEPTA platform.
Witnesses said they saw two people, later identified as Humphrey and Wilson, engaging in conversation on the east end of the platform before one of them, believed to be Humphrey, pulled out a gun and fired into the crowd, striking Welles.
SEPTA police said Humphrey is known to police after being arrested two years ago for a weapons offense, as well as last year for unauthorized use of a vehicle.
"It didn't stop him from reoffending. It didn't stop him from carrying a firearm illegally. It's frustrating," said Chief of SEPTA Transit Police Charles Lawson warned during a press conference last Friday.
Lawson described the shooting as a "lack of care for human life."
According to investigators, Humphrey boarded a train from North Philadelphia to go downtown. Once he was at the 15th Street station, he met up with the second suspect.
Shortly after meeting up, Humphrey then fired into a crowd on the platform, shooting a 16-year-old in the head. The victim was unresponsive and rushed to the hospital in critical condition.
Three SEPTA officers were "evidentially visible" on the platform at the time of the shooting, Lawson noted.
Investigators found six shell casings at the scene.
"Police found a jacket they believe that the suspect was wearing and wrapped up in the jacket was a semiautomatic handgun, so that is part of the scene," said Philadelphia Police Chief Inspector Scott Small.
Following the shooting, police took the two suspects into custody. Police said the relationship between the three is currently unknown, adding that there is no indication that the victim and the suspects communicated before shots rang out. However, law enforcement is still looking through hundreds of cameras in search of a motive.
"Our biggest crime issue on SEPTA is involving groups of juveniles. That's the pattern we have witnessed. Groups of juveniles meet up - bad things happen," Lawson said.
The shooting happened on the same day that Philadelphia District Attorney Larry Krasner announced he was suing to stop a new law designed to limit his authority on SEPTA crimes. Krasner says plans to appoint a special prosecutor who would investigate and prosecute crimes that occur on the city transit system is unconstitutional.
The attorney general's office was directed to appoint the new special prosecutor within 30 days, however, that deadline is Saturday. So far the attorney general said they have been unable to appoint one yet due to the narrow requirements set by the legislature.
Anyone with information on this incident is asked to call Philadelphia police at 215-686-TIPS or SEPTA police at 215-580-8111.
(Correction: A previous version of the story stated that the victim died on Saturday, based on information released by Philadelphia police. Investigators have since updated their report to say the victim died on Tuesday, Jan. 13.)