Travis Biehn enters court in Doylestown, Pa. (AP photo)

A 17-year-old Canadian faces up to four years in custody after being found guilty Monday of plotting to blow up his school in Pennsylvania.

Travis Biehn's case made headlines in the United States because he had made anti-American statements and wore an "I am Canadian" T-shirt to an early court appearance.

School officials in Doylestown, Pa., who alerted police about a bomb threat found written on a washroom wall, said the Grade 11 student was open about how much he disliked living in the U.S.

Biehn's parents are both from Newfoundland. The family has been living south of the border since 1997.

When Biehn's bedroom was searched, police found several kilograms of potassium nitrate, which can be used to make explosives.

He was charged with uttering terrorist threats and possessing incendiary devices.

Psychologists will interview Biehn over the next 20 days as the next step leading up to his sentencing.

The maximum penalty could keep him behind bars until he turns 21.

His defenders said Biehn was caught up in a post-9/11 witch hunt.

They pointed out that Travis and his father, Brant Biehn, a marketing executive at pharmaceutical company Merck, often launched rockets to entertain themselves and their neighbours.

They speculated the potassium nitrate was related to that hobby.