How do I kill ants coming out of an electrical socket?

I had an air freshener plugged into an electrical socket and it looked like the ants were laying their eggs on the air freshener! I threw away the air freshener and took off the plate but there was tons of ants crawling inside the wall. How can I safely kill these ants, without getting electricuted of course??? My husband went outside to see if he could find their trail leading into the house but found nothing.