Two teens were arrested for fatally shooting a Philadelphia track star who was just one day away from starting his freshmen year at Pennsylvania State University on a scholarship.

Taron Small, 16, and Byron Vinson, 15, were arrested on Wednesday in connection with the Aug. 13 shooting of 18-year-old Kristian Marche outside his home, Philly.com reports.

Small and Vinson are expected to face murder and conspiracy charges.

Homicide Unit Lt. Norman Davenport said Marche heard people attempting to break into the back of his parent’s home. After twice encountering the teens, Marche began walking away from them when Small shot him in the back of the head.

 “There was not a struggle, there was not a fight,” Davenport told Philly.com. “This is clearly a case of murder.”

Investigators believe the teens knew Marche, but the details of their relationship remain unclear. Police are also unsure why the teens allegedly targeted his home.

According to Davenport, this killing, took a serious toll on the investigators working the case.

At least 102 people age 18 or younger had been shot in Philadelphia in 2018 as of Monday, according to Philly.com.

“This case really hit a lot of detectives hard,” Davenport said. “We need to come together as a community and decide what we can do to make a change.”