A 17-year-old has pleaded guilty to four felonies in connection with threats directed at Plymouth-Canton high schools.
Brendan Sibel pleaded guilty to a terrorism threat, a 20-year felony, and a bomb threat, a 4-year felony.
Students at Canton and Salem high schools discovered threats written on a bathroom wall in each building.
The threats were determined to be non-credible. Sentencing will be later.