CSI has located the mother of Gil Grissom.
Tony Award-winner Phyllis Frelich has landed this key role and will appear in an episode tentatively scheduled for February 3.
Here's a rundown of what's on tap:
A murder will take place at a school for the deaf where the elder Mrs. Grissom is a teacher. She'll butt heads with Sara when that Mrs. Grissom shows up to investigate.
This episode will also feature Marlee Matlin - who we speculated could take on the role of Grissom's mother - as a school colleague who used to date Gil.