Investigators believe they have found the body of a teen girl who went missing in Pennsylvania this weekend.

The Schuylkill County coroner told local news station WNEP that a body was found in the search for 17-year-old Cassidy Derr, and it is believed to be the missing teenager.

The news station reports that Cassidy had gone with friends to Tuscarora Mountain near Tamaqua on Saturday night. She left the party on foot Sunday morning after getting into an argument with a friend.

Cassidy was last heard from later that morning when she contacted a friend, telling them she was lost and that her phone battery was about to die.

After a three-day search, investigators reportedly found Cassidy’s body on the mountain. Her cause of death is not yet known.

Cassidy was diabetic and carried an insulin pump that she needed to prevent a diabetic coma. It is not known if she had her insulin pump at the time she went for a walk alone.

An autopsy is reportedly scheduled for Thursday.

This is a developing story and will be updated as more information becomes available.

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