The Cincinnati Zoo is moving ahead with its lawsuit seeking the return of a 37-year-old gorilla from The Gorilla Foundation in California. The zoo filed additional court documents late Thursday in federal court in San Francisco.

Cincinnati Zoo officials are in San Francisco Monday for a court-ordered mediation with California-based The Gorilla Foundation.

Updated Dec. 17 at 7 p.m.

A judge in California is directing the Cincinnati Zoo and the Gorilla Foundation to work together on a solution to their dispute over a 37-year-old gorilla named Ndume.