In the 2008 film "Taken", Bryan Mills's former colleague who helps him is Sam Gilroy.
Sam is played by Leland Orser and is one of Bryan's trusted former associates. After Bryan's daughter Kim is abducted in Paris, Sam helps him track down the people responsible. His support matters because Bryan is operating under intense time pressure and needs someone with professional experience, contacts and an understanding of how dangerous the trafficking network is.
Bryan Mills is a retired Green Beret and former CIA operative whose specialized skills drive the rescue mission. Sam's role helps establish that Bryan has a wider circle of capable allies, even though Bryan personally carries out most of the investigation and pursuit. Another former associate, Jean-Claude Pitrel, also appears in the story, which can make the names easier to confuse.
Sam is not the film's villain or the person responsible for Kim's abduction. He is a former colleague who assists Bryan as the search moves through Paris's criminal underworld. The character returns in later Taken films, reinforcing his place among Bryan's trusted contacts.