Shaler Township Police are at work in the 1400 of Anderson Road near Shaler Area High School which is on lockdown.
A law enforcement source tells KDKA's Marty Griffin a mother called 911 after finding a gun on her teenage son's bed.
The teen demanded the gun back, but the mother refused. That is when the teen took off into a wooded area.
The teen is wanted on gun charges and is expected to be charged as a juvenile.
Police say the perimeter of nearby Shaler Area High School is secure and there is no immediate threat to the school and are also asking the public to avoid the area.
We expect to speak with the police chief soon for further details.
Officials add that the teen has not made any specific threats against anyone.