09/14/2011 11:42 EDT | Updated 01/12/2012 02:20 EST

Incendiary device may have caused Swissair crash; ex-Mountie tells CBC

HALIFAX - CBC's Fifth Estate is reporting that a former RCMP officer involved in the investigation into the crash of Swissair Flight 111 off Nova Scotia believes an incendiary device may have brought down the plane.

Tom Juby has told Fifth Estate that he was prevented by senior RCMP and aviation safety officials from pursuing his theory that the crash may have been caused by a criminal device.

The flight from New York to Zurich crashed into the Atlantic Ocean off Peggy's Cove on Sept. 2, 1998, killing 229 passengers and crew.

A Transportation Safety Board investigation concluded the plane was brought down by a fire in the cockpit that was caused by sparking electrical wires.

Juby, a former arson investigator who worked on the Swissair file, told the CBC that the TSB investigation was done "improperly" and that high levels of magnesium -- a key ingredient in an incendiary device -- were discovered in the cockpit area.

The Fifth Estate, which will broadcast the item Friday night, says it spoke to several other investigators and a federal scientist who support Juby's suspicions.

The CBC says the RCMP and the TSB repeatedly refused to comment about Juby's allegations.