Internal Affairs Bureau Agent Sergeant Rick Stetler (David Lee Smith, season 2-), IAB Sergeant and Horatio's personal nemesis. He later starts a relationship with Yelina, but she leaves with
her husband on season 3 finale. His harsh feelings toward Caine stem from a bitter feeling when Horatio was promoted to lieutenant
instead of him, believing Caine may have pulled in some "special favors" for the job. Horatio also suspects that during Stetler's
relationship with Yelina, Stetler may have been abusive, which is evident when she comes to work one day with a black eye.
(Season 3, episode Crime Wave) Stetler later returns to warn Horatio against going after a corrupt city official, saying that he can't protect him if Caine
follows through. "Just like old times," the CSI replies (episode 517, "A Grizzly Murder").
WFOR-TV Newscaster Erica Sykes (Amy Laughlin, Season 3-), an aggressive ambitious young news reporter for the Miami
CBS station, WFOR-TV. Her antics are often described as crazy and are very much annoying to the CSI team.
She may or may not have dated Ryan at some stage, but the two often flirt. It is Erica who revealed to Ryan that there is
a mole in the lab in a special extended scene that was available on www.cbs.com after the episode Urban Hellraisers aired. She also helps Ryan in a case regarding abuse of eminent domain, with the
government evicting people from their homes before turning the land over to a private developer (episode 505, "Death Eminent").
In a later episode, however, she puts the life of Natalia's sister at risk by mentioning on the air that she is a victim in
a kidnapping (episode 508, "Darkroom").
FBI Agent Glen Cole (Mark Rolston), a FBI Agent, headed the investigation into the lab in season 4, returns in season 5 working on a case involving counterfeitting
and the Korean Government (episodes 425, "One of Our Own;" 503, "Death Pool 100").
MDPD Homicide Detective Jake Berkeley (Johnny Whitworth, Season 5-), a former undercover officer with the MDPD narcotics unit, as of episode 512 ('Internal Affairs') he has moved
to being a homicide detective. He and Calleigh dated while they were in the academy. At the end of season 5, it shows them
in a relationship again
MDPD Detective John Hagen (Holt McCallany, seasons 1-3), a homicide detective who had emotional and psychological problems.
Raymond Caine's partner prior to his faked death, he told Calleigh once that he couldn't stand being reminded of being the
partner of a dirty cop. He also had a brief relationship with Calleigh in Season 2. While pulling a crucial piece of evidence
from a crime scene, he panicked when Calleigh came over to photograph the scene; he then crept up behind her and put his gun
behind her head. Although he didn't mean to hurt her, it allowed him time to escape (she didn't know it was him at that time).
He later shot himself in the Ballistics Lab right after Calleigh turned around to walk out of the lab during the Season 3
MDPD Officer Aaron Jessop (Joel West season 4) A patrol officer, Jessop joined the force at about the same time Ryan Wolfe
was moving over to CSI. While he thought like a cop, he also was able to think like a CSI. This was evident in the episode
The Oath where he was able to help Calleigh and assess the crime scene and upped the charge and
penalty. Jessop was killed when he opened a cabinet rigged with a hand grenade booby-trap at the scene of a Mala Noche shootout. (West had previously appeared
as Officer Ramirez in one episode during Season 2)
Laboratory Technician Carrie Delgado (Nicole DeHuff, season 2), Blood evidence technician. Was a fan of Quincy, M.E. as a child, influencing her to become a criminalist.
Laboratory Technician Jim Markham (Joshua Leonard, season 3), Ballistic lab tech. Markham became the head of the ballistics section when Calleigh left, but was quickly demoted
after Calleigh discovered that Markham took short cuts.
Assistant State Attorney Rebecca Nevins (Christina Chang), An Assistant State Attorney who briefly had a relationship with Horatio, but
he broke it off when she made a deal with a criminal suspected of killing a cop and series of robberies as well as having
a relationship with a 16-year-old girl who took part in his crimes. Originally expected to be a more regular character but
has not appeared on the show since that episode for reasons unknown.
Assistant State Attorney Monica West (Bellamy Young, season 4). An Assistant State Attorney who replaced Nevins. She was the one who
planted Boa Vista
to spy on the CSI Lab, hoping she will come up with evidence of corruption within the lab. However, when Natalia only brought
back positive results on the lab, she got frustrated enough that she stole some money that the team seized in a raid on the
Mala Noches when her fiancee, Agent Peter Elliot, was looking over the money, and tipped off the FBI causing the lab to be
investigated. When Wolfe pointed out that the money wasn't taken from their lab, Calleigh figured it out and had Elliott confess.
Calleigh made him get Monica to admit that she was the one who took the money. She was then arrested.