A man has been fined after he tried to bring a pipe bomb through security at Edmonton International Airport — and was allowed to board his flight anyway, according to a CBC report.

The Canadian Air Transport Security Authority (CATSA) confiscated the device and allowed the man to get on the Sept. 20 flight, but then the agency alerted RCMP four days later, the broadcaster reports.

Cops arrested Skylar Vincent Murphy, 18, of Spruce Grove, Alta., on Sept. 27, and charged him with possession of an explosive substance.

"The RCMP investigation indicates that the charge stems from an isolated incident, and that no other individuals were involved," Sgt. Josee Valiquette said in a statement about the arrest.

Last month, Murphy pleaded guilty and was given a $100 fine and one year's probation, the report says.

When questioned by the CBC as to why Murphy was allowed to board the flight, a CATSA spokeswoman said screeners don't have the authority to make arrests, only to alert police.