Ottawa police say they have closed an investigation into a report that a gunman showed up at the home of an Air Canada executive, saying a witness could not confirm whether there was a gun.

Police were called to the home of Air Canada vice-president Duncan Dee last week after a security guard said a man threatened him with a gun and then drove off.

Police searched the surrounding area but were unable to locate a suspect.

Ottawa police spokesman Const. Henri Lanctot said Thursday that further investigation revealed the security guard could not confirm the existence of an actual gun. Police now consider the case closed.

Dee has been Air Canada's chief spokesman during the airline's current contract dispute with its unionized flight attendants.

The reported incident came just after the federal government referred a dispute between the two sides to the Canada Industrial Relations Board, a move which took away the company's ability to lock workers out and also prevented the flight attendants from going on strike.