By Oren Liebermann, Dan Wing

SKIPPACK TWP., Pa. (CBS) – The Montgomery County Prosecutor’s office and Pennsylvania State Police have arrested a 16-year old boy on charges that he murdered his 17-year old girlfriend Saturday night.

Authorities say Tristan Stahley and Julieanne Siller were overheard arguing at Stahley’s residence on Rittenhouse Lane in Skippack Township, before leaving a short time later for nearby Palmer Park.

Authorities say the couple continued arguing there until Stahley stabbed Siller in the throat. He continued stabbing her before dragging her body off a walking trail into a densely wooded area.

Stahley then returned home, where State Police were called around 10 p.m. for an altercation between the teen and his father. The 16-year old was taken into custody, and investigators found the victim’s body at the park a short time later.

Friends of the victim say they tried to warn her about her boyfriend and his troubles.

“We always told her to keep your distance and break it off,” said the victim’s friend, Rhett McDonald.

Siller was a senior at Spring Ford High School and was headed to Penn State Altoona in the fall, until everything went wrong Saturday night.

“She made my day,” McDonald said. “First person I saw in the morning, last face I saw when I left. She will be terribly missed.”

Friends set up a small memorial for Siller, a place to mourn the loss of a young girl who made everyone around her feel welcome and smile. She was set to graduate on June 18th.

Stahley was charged with first-degree murder Sunday and sent to the Montgomery County Prison with no bail.

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