A man who had a pipe bomb in his carry-on bag was still allowed to board his international flight from Edmonton last fall, even after screening officers seized the explosive device from him.

Skylar Murphy, 18, pleaded guilty last month to possession of an explosive substance in connection with the September incident at the Edmonton International Airport.

He was sentenced to a year of probation and fined $100.

When screening officers found what court documents describe as black powder and a pipe bomb inside the passenger’s carry-on bag on Sept. 20, 2013, they seized the suspicious items but still allowed him to board an international flight.

It wasn’t until four days later that Canada’s Air Transport Security Authority (CATSA) called the RCMP.

Three days after that, on Sept. 27, Murphy was arrested upon his return to Canada. CATSA would not reveal his travel destination.

CATSA is also not saying why the passenger was allowed to get on his flight and why it took so long to notify police.

“CATSA screening officers do not have the authority to apprehend or detain passengers,” spokesperson Mathieu Larocque said.

He also told CTV News that, “for security reasons, I can’t go into details about our procedures at the checkpoint, which include our protocols with the police.

“Incidents that occur at our checkpoints are constantly being reviewed. We are constantly reviewing and updating our procedures and training to ensure that screening officers are equipped to handle all sorts of security situations.”

Murphy has declined comment.

One security expert, Andre Gerolymatos of Simon Fraser University, said it appears that “everyone is dodging the bullet” in this case.

“No one wants to take responsibility for what is obviously a series of mistakes.”

He also said the incident defies logic.

“If a person is carrying an explosive device in their carry-on, they should not be allowed to board the airplane. That is just common sense.”

With a report from CTV’s Alberta Bureau Chief Janet Dirks