Manheim departed the series following Sam Waterston, who announced his exit in February as District Attorney Jack McCoy.
Tony Goldwyn later joined as the new district attorney.
Its the longest-running law enforcement series on TV.
Maura TierneyGilbert Flores/Getty Images
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Dick Wolf is creator and executive producer.
The new season starts Oct. 3 at 8 p.m. on NBC and next day on Peacock.
Tierney can currently be seen co-starring in UniversalsTwisters.
TVLine was first to report Tierneys casting.
