Investigators are looking for three male suspects after a failed robbery at a cargo yard in Halton Hills early Sunday morning where a lone security guard was held at gunpoint.

Halton Regional Police say that at 2:30 a.m. two trucks without trailers approached the gates of the yard in the Steeles Avenue and Winston Churchill Bouelvard area.

The drivers began to speak with a security guard posted at the gate when police say a third suspect approached the guard from behind, allegedly put in in a head lock and pointed a gun at him.

The suspect then demanded that the guard open the gate to the yard.

Before he could comply, police say the drivers of the trucks realized they could be seen by surveillance cameras posted at the yard and all three males fled the scene.

The guard was not injured in the encounter.

“Police credit his calm demeanour in ensuring that no harm came to himself,” investigators said Sunday.

The trucks used in the incident were allegedly stolen earlier in the Oakville area.

Police described two of the suspects as black males with Caribbean accents.