U.S. Marshals have arrested 35-year-old Dante Abdul Malik on charges of hindering apprehension and tampering with evidence.
Abdul Malik is the stepfather of 16-year-old Azzubair Outen-Fleming, who was arrested in connection with the fatal June 6 shooting.
Another suspect, 16-year-old Kaiseem Smith, is still being sought. Both 16-year-old suspects are facing murder charges.
READ MORE | Police name 2 suspects wanted in killing of Penn State student Billy Schmidt
Police name 2 suspects wanted in killing of Penn State student Billy Schmidt
Surveillance video captured the moments leading up to the shooting, according to investigators. Authorities allege the suspects stole Schmidt's cellphone on the 1900 block of Durfor Street on June 6. As Schmidt chased after the suspects, one of them turned and shot the Penn State senior in the chest.
Schmidt was pronounced dead a short time later.
Philadelphia District Attorney Larry Krasner said investigators believe Smith was the gunman.
"The information that we have seems to indicate Kaiseem Smith is the shooter in this case," said Krasner.
Schmidt's father, William Schmidt, said he is encouraged that progress is being made in the investigation, but said no development can undo the loss of his son.
"There's nothing that's going to bring him back. So, nothing is going to be enough for me," he said.
William Schmidt also said living near the location where his son was killed has become unbearable.
"It was just me and him here, and you know, it's a three-bedroom house. So, I just need to get out, right now," he said.
Authorities said up to $30,000 in reward money is being offered for information related to the case. Anyone with information on the case is asked to contact Philadelphia police or the U.S. Marshals Service.