Usually detectives catch thieves... but given magpies like Merrick are REALLY good at finding and collecting items, he does... both?
Merrick doesn't put himself on the side of good or bad. His job is, quite simply, to find things for people. Whether that means finding it or stealing it, he'll do it for the right price.
This sly bird chooses not to wear clothes for one reason--less things to get ripped if he has to make an escape. He always frets over trying to conceal things in a pocket and then losing whatever coat or pants he had on the run. A 'nudist born of paranoia,' he elects to tuck things carefully in his thick feathers, or just books it depending on size.