In House M.D. season 5, House hires private investigator Lucas Douglas to investigate Wilson.
Lucas is played by Michael Weston and first appears when House wants information about his friend’s private life. House is curious about Wilson’s new relationship and uses Lucas to gather details that Wilson would not willingly share.
The arrangement demonstrates House’s unusual approach to friendship: instead of asking directly, he turns a personal question into an investigation. Lucas is initially a tool in House’s plan, but he becomes a recurring character and later works with House on other matters.
Lucas is sometimes confused with Michael Tritter, another season 3 character who investigates House through a police and legal conflict. Tritter is a police detective, while Lucas is a private investigator hired by House.