Lucas Douglas is the licensed private investigator hired by Dr. House in the House, M.D. television series.
Lucas first appears in the sixth-season episode “Not Cancer,” when House uses him to investigate patients and other people connected to his work. His unconventional methods make him useful for gathering information that hospital staff cannot easily obtain through ordinary clinical channels.
The character is played by Michael Weston. Lucas later becomes involved in House’s personal life and develops a relationship with Dr. Lisa Cuddy. His presence provides a different kind of investigative perspective from House’s medical deduction: Lucas searches records, observes people, and performs practical surveillance.
Lucas is sometimes confused with Michael Tritter, a police detective whose conflict with House drives a separate storyline. Tritter investigates House after a clinical encounter, whereas Lucas is a private investigator working at House’s request.