He claims to have an amazing sixth sense for solving crimes. While looking for Snowy, he gave Tintin another woman's dog, named Fritzy. The woman hit MacAdam over the back of the head and took her dog back. Following his bringings of many dogs that are mistakenly different breeds, Tintin eventually dismisses MacAdam and manages to find Snowy himself. Later on, with the kidnapping of Tintin, MacAdam was summoned by the police as he found Snowy, and they went off to find Tintin. When he gets distracted by lighting a cigar, a man, presumably Sam, grabbed both MacAdam and Snowy leading to the death of MacAdam.
- He might be the American version of Thompson and Thompson. LIke the twins, he is clumsy and incompetent at doing his job.