Sonya

From Wiki 24

Sonya
Season	The Game
Mentioned in	Chase Found Out
Status	Alive

Sonya was a CTU officer familiar to Chloe O'Brian and Chase Edmunds. She was mentioned in a conversation between these two agents. Chase stated that he needed a flight to Los Angeles. Chloe responded that Sonya would never go for it just so Chase could handle the mission, since there were competent agents already present there.

It is implied Sonya worked with Chase and Chloe at CTU Washington, and may have been Special Agent in Charge.