OMAHA, Neb. (AP) — Officials aren’t sure what’s killing the fish piling up along the shore of a lake in west Omaha.

Brook Bench is director of the Omaha Parks, Recreation and Public Property Department, and he said it’s not the first fish kill reported at Lake Zorinsky.

Omaha Public Works asked people to stay away from the lake in June after a storm-related power outage at a nearby sewage lift station caused let untreated sewage flow overland into the lake. That advisory was later lifted. It’s unclear whether the sewage intrusion is involved in the fish kill, however.