The teens were found dead in a wooded area near Ferndale Road in New Philadelphia Borough early on Oct. 10, authorities have said.
Now, troopers believe 18-year-old Mock and 16-year-old Caraballo had gone to the wooded area known as "the Sanchez" to go target shooting with two other people on the night of Oct. 8.
The four "remained in the area for a short period of time," before Mock was fatally shot in the head and Caraballo was stabbed to death, according to investigators.
One suspect walked out of the woods, got in his car, and drove west toward the Borough, troopers believe. The other fled through the forest, crossed "several bodies of water," and later sought assistance from homeowners at a nearby residence, police said.
PSP is now offering a $4,000 reward for information that leads to the killers. Call the Frackville station at 570-874-5300 or submit a tip anonymously via Crimewatch.
Click here to follow Daily Voice Reading and receive free news updates.