Topeka ? A 17-year-old Lowland gorilla has died at the Topeka Zoo.

And a medical examination is planned to determine the cause of death for M’Bili. He hadn’t been showing any outward signs of illness or distress before being found dead Saturday morning in his night quarters.

Lowland gorillas typically live between 40 and 50 years in captivity.

The death comes amid controversy at the zoo. The Association of Zoos and Aquariums recently agreed to conduct an independent, top-down review of the zoo.

City Manager Norton Bonaparte had sought the review after federal inspections in the prior two months highlighted questionable care that led to numerous animal deaths at the zoo in recent years.