The Canadian Air Transport Security Authority says it should have called the RCMP sooner after discovering a pipe bomb inside a carry-on bag belonging to a passenger who was still allowed to board his flight out of Edmonton last fall.

After Transport Minister Lisa Raitt slammed CATSA on Wednesday, saying the four-day delay in contacting the RCMP was “unacceptable,” a spokesperson for the security authority said screening officers should have reacted differently to the Sept. 20, 2013 incident.

After a full review, “CATSA concluded that the RCMP should have been contacted earlier in the process as per our procedures,” Mathieu Larocque said.

“Corrective actions have been taken and those involved in the incident were disciplined and required to take additional training. We have also updated screening officers’ training material across the country and put more emphasis on our procedures,” he said.

Skylar Murphy, 18, pleaded guilty last month to possession of an explosive substance after black powder and a pipe bomb were found in his carry-on bag at the Edmonton International Airport nearly four months ago.

But even though screening officers seized the suspicious items, Murphy was allowed to board an international flight. It wasn’t until four days later that CATSA notified the RCMP.

Murphy was arrested on Sept. 27, upon his return to Canada. After pleading guilty in an Alberta court, he was sentenced to one year of probation and fined $100.

Details of the incident did not emerge until this week.

In a brief statement Wednesday, Raitt criticized CATSA and said Murphy should have never been allowed to board his flight.

She said “it is unacceptable that CATSA waited four days before seeking the RCMP's assistance.”

Raitt also said she would be calling the president of CATSA “to ensure the organization takes further action to better protect the safety of Canadian travellers.”

Michael Kempa, an associate professor of criminology at the University of Ottawa, told CTV’s Power Play Wednesday that it’s “unbelievable” CATSA took four days to call the RCMP.

“And if there was any confusion as to what the scanning agent should have done, that’d be the very basic level of training,” he said.

While CATSA’s defence that its agents are not authorized to arrest anybody is “definitely the case,” Kempa said “there is a whole network of actors at the airport that are supposed to be mobilized to, first of all, prevent the person from getting on the plane, perhaps take them in the backroom for more careful searching and then bring the police in.”