LOS ANGELES - CBS says "Matrix" star Laurence Fishburne is joining the cast of "CSI: Crime Scene Investigation," stepping into the gap left by departing cast member William Petersen.

CBS tells The Associated Press that Fishburne will be introduced in the ninth episode of the upcoming season. He plays a college lecturer and former pathologist who is focused on why people commit acts of violence.

Petersen, who has been with the series since it debuted in fall 2000, will leave the show early next year. CBS says the air date for Petersen's final episode hasn't been determined.

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