<P> The first actor to be cast for the show was Dann Florek . Florek had originated the character of Captain Don Cragen in the 1988 pilot for Law & Order and played the character for the first three seasons of the show until he was fired on the orders of network executives, who wanted to add female characters to the all male primary cast . He maintained a friendly relationship with Wolf, however, and went on to direct three episodes of the original series as well as to occasionally guest star on the show . Shortly after Florek reprised his role for Exiled: A Law & Order Movie, he received a call to be on Sex Crimes . Initially reluctant, he eventually agreed to star on the show as Cragen on the assurance that he would not be asked to audition for the role . </P> <P> Shortly after the cancellation of Homicide: Life on the Street, Richard Belzer heard that Benjamin Bratt had left Law & Order . Belzer requested his manager to call Wolf and pitch the idea for Belzer's character from Homicide, Detective John Munch, to become the new partner of Jerry Orbach's character, Detective Lennie Briscoe, since they had previously teamed in three Homicide crossovers . Wolf loved the idea, but had already cast Jesse L. Martin as Briscoe's new partner, Detective Ed Green . The idea was reconfigured, however, to have Munch on Law & Order: Special Victims Unit instead . Since the character of Munch was inspired by David Simon's depiction of Detective Sergeant Jay Landsman and developed for Homicide by Tom Fontana and Barry Levinson, the addition of Munch to the cast required the consent of all three . The appropriate agreements were reached and, while Fontana and Levinson agreed to waive their royalty rights, contracts with Simon required that he be paid royalties for any new show in which Munch is a main character; as a result, Simon receives royalties every time Munch appears in an episode of the show . </P> <P> Dean Winters was cast as Munch's partner, Brian Cassidy, at the insistence of Belzer . Belzer looked at Winters as a sort of little brother, and told Wolf, "Well, I'll do this new show of yours, SVU, only if you make Dean Winters my partner ." Wolf did make Winters Belzer's partner, but he was contractually obligated to his other show at the time, the HBO drama Oz . Since the role on Law & Order: Special Victims Unit was only initially meant to be a few episodes, Winters was forced to leave when it was time to film Oz again . Winters returned for the Season 13 finale, "Rhodium Nights," reprising his role as Cassidy . He also appeared (as Cassidy) on the two - part Season 14 premiere "Lost Reputation" / "Above Suspicion". He subsequently became a recurring character into season 15 . The void left by Winters's departure was filled for the remainder of the season by Michelle Hurd as Detective Monique Jeffries, a character who Wolf promised that, despite starting out as a minor character with one scene in the pilot, would eventually develop . Hurd left the show at the beginning of season two to join the cast of Leap Years . Munch's permanent partner came in the form of rapper - turned - actor Ice - T, who had previously worked with Wolf on New York Undercover and Exiled . Ice - T originally agreed to do only four episodes of Law & Order: Special Victims Unit, but he quickly gained affection for the ensemble nature of the cast . He relocated to New York City before his four - episode contract was up and remained with the show as Munch's permanent partner, Detective Odafin "Fin" Tutuola . </P> <P> Initially, the show focused exclusively on the policework of the detectives in the Special Victims Unit of the 16th precinct, with members of the District Attorney's office occasionally appearing as guest roles crossing over from the original Law & Order . From season two onwards, the format was changed to be more faithful to the original Law & Order concept by including court cases . Stephanie March had little television experience before being cast on Law & Order: Special Victims Unit, nor did she watch much TV . Nevertheless, March was cast as Assistant District Attorney Alexandra Cabot at the beginning of season two but still believed that, due to the grim nature of the series, it would be short - lived . She stayed with the series for three seasons, however, and left when she believed she had reached the natural conclusion of the character's development . She would later reprise the character as a guest appearance in season six and as a regular character on the short - lived Wolf series, Conviction, where she was promised more to do . Diane Neal had previously guest starred on Law & Order: Special Victims Unit in season three before being cast as Cabot's replacement, Casey Novak, in season five . Neal remained with the show through the end of season nine, after which she was replaced by Michaela McManus . March returned to the show in the tenth season (after McManus' departure from the cast) when Neal Baer proposed Cabot receive a character arc to revitalize the second part of the season, which would continue through season eleven . </P>

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