Gardai arrested a man in his forties in Castlebar on Saturday after an attempted robbery to a convenience store in the town.
The incident at Mulroy's, on the Moneen roundabout which occurred at 1pm, involved a male shop worker being threatened with a knife when he pursued a man who fled the scene without paying for some items.
Gardai and members of the armed support unit went to a house in the town where they were confronted by the man carrying two knives in a threatening manner.
Eventually the man was disarmed and arrested.
A file is being prepared for the DPP.