Warrick Brown is a fictional character in the CBS crime drama CSI: Crime Scene Investigation, portrayed by Gary Dourdan. Warrick appeared in every episode until his death in season nine, with the exceptions of "After the Show" from season four, "Crow's Feet" and "Committed" from season five, and "The Chick Chop Flick Shop" from season eight.

Warrick Brown, born in 1971, was a Las Vegas native, whose father abandoned him soon after his birth, and whose mother died when he was seven years old. Raised by his grandmother and Aunt Bertha, Warrick found it very difficult to socialize, and could often be found with his head in a book. His love of mathematics and science took him to Western Las Vegas University, where he earned a Bachelor of Science in Chemistry.

Warrick grew up in a strict household, and kept his position as a casino runner a secret from his grandmother. He once told Catherine that while he was a dork in high school, and still had dimples, he "got a little action". He was strongly influenced by a community organizer who ran a center that he spent time at after school.

Catherine Willows (née Flynn) was a fictional character on the CBS crime drama CSI: Crime Scene Investigation, portrayed by Marg Helgenberger, who has received two Emmy nominations and two Golden Globe nominations for the role. Catherine Willows was employed as a crime-scene investigator supervisor (a "CSI-3") and forensic scientist for Clark County, Nevada, which contains the city of Las Vegas. In Season 12, the Willows character was switched to an FBI Special Agent role before she left the series.

Catherine appeared in every episode through the January 25, 2012, episode "Willows in the Wind" (Season 12: episode 12), with the exceptions of "Random Acts of Violence" from season three, "Hollywood Brass" and "Committed" from season five, and "House of Hoarders," "All That Cremains," and "Unleashed" from season eleven.

Catherine Willows is listed as number 82 on Bravo's 100 Greatest TV Characters, along with Gil Grissom, her mentor on the show.

Helgenberger discussed her upcoming departure from CSI on the January 18, 2012, The Late Show with David Letterman, a week before that episode would air.

Gary Dourdan (born December 11, 1966) is an American actor. He is best known for portraying Warrick Brown on the television series CSI: Crime Scene Investigation.

Dourdan was born Gary Robert Durdin in Philadelphia, Pennsylvania, the son of Sandy, a teacher and fashion designer, and Robert Durdin, an entrepreneur and agent for jazz musicians. Dourdan is the second youngest of five children. When he was 6 years old, his older brother Darryl was murdered while on vacation in Haiti; the case remains unsolved. He moved with his family to Willingboro, New Jersey when he was in his youth. At this time his interests included acting, music, and martial arts. Later Dourdan moved to New York City and worked as a doorman at a rehearsal studio, where he met some of Manhattan's promising young artists.

Dourdan played in several bands in New York City in the early 1990s and acted in regional theatre around the tristate area. He received his first break when Debbie Allen cast him as Shazza Zulu on A Different World, based on a tape of him in an avant-garde play. In 1996, Dourdan appeared in the Lois & Clark: The New Adventures of Superman episode "Never On Sunday", where he played an assistant. In 1997, Dourdan played the character Christie, the first mate, crack-shot, and second in command of the spaceship Betty, in the film Alien Resurrection. He also appears in the films Playing God and Thursday, and on television starred in the Dick Wolf production Swift Justice and played a recurring role on the Showtime series Soul Food until he nabbed the part of Warrick Brown on CSI: Crime Scene Investigation. In 2007, he played the character Cameron, the boyfriend of Rowena Price (played by Halle Berry), in the film Perfect Stranger.

Nicholas "Nick" Stokes is a fictional character on the CBS crime drama CSI: Crime Scene Investigation, portrayed by George Eads. Nick has appeared in every episode except for "Blood Lust" from season three, "Jackpot" and "Butterflied" from season four, "Committed" from season five, "Spellbound" from season six, and "Genetic Disorder" from season twelve.

George Eads is one of only two actors to have been part of the main cast for every episode of the show, with Paul Guilfoyle sharing the honor. Fellow castmates Eric Szmanda, Robert David Hall, David Berman and Jorja Fox have also been on the show since its inception in 2000. (Fox left the cast in the middle of Season 8, appearing sporadically before returning in Season 10.) Eads signed to appear in season 13.

Nicholas "Nick" Stokes was born in Austin, Texas to Judge Bill Stokes and Lawyer Jillian Stokes. Nick is the youngest of seven siblings (it is mentioned in "Revenge is Best Served Cold" that he has at least one brother), and throughout his childhood, he exhibited considerable athletic and academic potential. In the episode "Bloodsport", Nick tells Raymond Langston, "I'm from Austin. I grew up playing football."

Sofia Curtis is a fictional character on the CBS crime drama, CSI: Crime Scene Investigation, portrayed by British actress Louise Lombard.

Sofia was introduced in the season five episode "Formalities". It is later explained in the season six episode "Bodies in Motion" that, though she qualified to become a detective, the sheriff "pulled her papers" and assigned her to CSI due to her lab skills. Due to a struggle in office politics, Conrad Ecklie demoted her from acting day shift supervisor (season 5 episode "Mea Culpa") to night shift; she subsequently thought about quitting. Gil Grissom talked her into staying, and in season six she resumed her original career path and returned to police work as a detective, like her mother. She originally took a position in Boulder City, but transferred back to Las Vegas in the first episode of season six. In the two part episode "A Bullet Runs Through It", she believes that she may have accidentally shot and killed Officer Daniel Bell in a wild shoot out with drug dealers. The shooting causes her great anxiety and emotional stress, but forensic investigation eventually proved that Captain Jim Brass was the accidental shooter (the officer had unwittingly stood up in Brass's line of fire). Later, Curtis is horrified to discover that she had actually watched an undercover cop die on camera from carbon monoxide poisoning. Though she takes it more calmly than the incident with Officer Bell, she still feels responsible for the officer's death (season 7 episode "Monster in the Box").