David Reed is a captain for the Los Angeles County Sheriff's Department.
David Reed takes his job as a deputy sheriff very serious, especially as a captain. He's got some kind of rivalry as well as hostility with Captain Brooks Avery. He even seems to take his job even more seriously than the way Avery takes his, or the way any other officer takes.
Years ago, Captain David Reed and Captain Brooks Avery of the LAPD planted evidence to convict a murderer after previous evidence was excluded from trial; Avery was prepared to resign over the incident when it came to light, but another LAPD police officer, Roger Murtaugh convinced Avery to stay because if his impropriety was revealed it would mean that all of Avery's cases (many of which he worked with Murtaugh) would be reviewed if not overturned entirely.