One good “Mystery!” deserves another, especially in the case of one of 1992’s most acclaimed programs. A year ago, “Mystery!” got rave reviews and its highest ratings to date for “Prime Suspect,” a drama that starred Helen Mirren as a skilled British police detective fighting sexual discrimintion on the job as she lead the hunt for a murderer. On Thursday, Mirren reprises her role as Detective Chief Inspector Jane Tennison in the new four-part sequel “Prime Suspect 2.” This time Ttennison is investigating a murder in a London neighborhood distrustful of police. At the same time, she’s involved in an interracial romance with a colleague (Colin Salmon).

Royal Shakespeare Company veteran Mirren says it’s “great” to have another chance to play the character, “because you change within yourself in that period of time, and my interest is in bringing exactly who I am at a given point into the part, and to allow it to change with me. (Tennison) is going to change and develop over the three or four years that I’m playing her.” Helen Mirren and Colin Salmon star In ‘Prime Suspect 2,’ beginning Thursday.

“Prime Suspect III” is in the works, with the script being ] finalized for filming later this year. Mirren says tliat the international success of the original “Prime Suspect” prompted the suggestion that it become a regularly scheduled series, “… and we did discuss that before we made this second story, that it might be time to change the format and make it more like an ‘Inspector Morse’ type of thing, but I resisted that idea. You just can develop character and story much more successfully within the long format of a fourhour drama.” With a background in such diverse projects as “Macbeth” and the controversial movie “The Cook, the Thief, His Wife and Her Lover,” Mirren says she has tried not to repeat roles in her career. However, she concedes, “I’ve played Cleopatra twice, so I guess you could call that a recurring part, too ”