Grooms was a federal agent with the Bureau of Alcohol, Tobacco and Firearms, and later the Federal Bureau of Investigation. Assigned to San Francisco, he headed the investigation into the bomb murder of Amanda Babbage. Inclined to dismiss Leland Stottlemeyer as an amateur and Adrian Monk as an oddity, he quickly hit on Amanda's kid brother Ricky as the likely suspect, since he was the only person with a motive who could have sent the bombs. Grooms was amused and derisive when Monk suspected the elder brother, Brian, who had been in a coma for four months. However, Monk was eventually proved right, and the agent gained a new respect for his abilities.