After the battle of Culloden he was appointed, through the instrumentality of Lord Loudon, to fill the situation of an officer of excise, in Ayrshire; and notwithstanding the unpleasant nature of his employment, he succeeded, by his courtesy, in obtaining the good-will of all his neighbours, all of whom, with the exception of the Earl of Eglinton, gave him permission to kill game on their estates. It was his misfortune to live immediately adjoining the property of his lordship; and it would appear that the noble earl having once detected him in killing a hare, warned him not to commit a similar offence again. Mr. Campbell apologised for the trespass of which he had been guilty, and excused himself by stating that he was in search of smugglers, and that having suddenly started the hare, he was surprised, and without thinking, he shot it. The ill-will which was raised in his lordship's mind by this circumstance, was in nowise removed by some proceedings which Mr. Campbell was compelled to take against Bartleymore, one of his servants, for smuggling; and it appears that his lordship's death was eventually attributable to the steps which he took at the instigation of this very person. About ten in the morning of the 24th of October 1769, Campbell took his gun, and went out with another officer, with a view to detect smugglers. Mr. Campbell took with him a licence for shooting, which had been given him by Dr. Hunter, though they had no particular design of killing any game, but intended to shoot a woodcock if they should see one.