Chie is a human photographer and information broker. She is a long-time friend of Shuu Tsukiyama, aware of his secret but uninterested in exposing him as a Ghoul. At his request, she serves as an informant to Kaneki's group.
She seeks out the members of the Quinx Squad, and offers to sell them information pertaining to Torso. This is because she has an unusual interest in their leader, Sasaki.
(Source: Tokyo Ghoul Wikia)