Peter Anthony Houston was convicted of building the bomb planted in this restroom. ((Betsy Trumpener/CBC))

A B.C. man has been convicted of building a potentially deadly pipe bomb that was planted in a highway restroom in northeastern B.C. in 1999.

The bomb was left at a rest stop on Highway 29 between Fort St. John and Hudson's Hope, B.C.

Packed with black powder and rocket fuel, it was set up to explode when the washroom door was opened, but it failed to detonate.

Peter Anthony Houston, 32, was eventually arrested and charged with attempted murder and intent to cause an explosion, but the case was never made public and took years to go to trial.

Neil MacKenzie, a spokesman for the B.C. Crown, said Houston ultimately pleaded guilty to charges connected with construction of the bomb and possession of an explosive substance.

"Ultimately, Crown was not left with any completely clear picture as to his motivation," MacKenzie said.

Bomb posed serious threat, court heard

During Houston's trial in September 2008 at the B.C. Supreme Court in Fort St. John, experts testified the bomb could have detonated with the force of a military grenade and caused a "very serious explosion" that would likely have caused bodily harm or death, and considerable property damage.

Four days into the trial, on Sept. 8, Houston pleaded guilty to the two lesser charges of intent to cause an explosion and possession of an explosive substance.

The same day, Houston was given a conditional sentence of two years less a day, to be served under house arrest in Prince George, where he lives with his wife and children.

He was also handed three years probation, and a 10-year prohibition on firearms ownership.

Houston admitted he built the bomb "with intent to cause serious bodily harm," but did not admit to planting the bomb in the restroom.

In a court transcript obtained by CBC News, Justice Baker states that Houston was motivated by "certain political views," but she didn't provide any details.

In April, Houston successfully convinced a judge to loosen the conditions of his house arrest and apply "a form of more liberal daytime absences."

Houston can now leave his house from 8 a.m. to 6:30 p.m. PT to "earn a living to support his family."

with files from Betsy Trumpener