ASHEBORO, RANDOLPH COUNTY -

A female sea lion has died at the North Carolina Zoo, approximately one month after its arrival.

Zoo officials said "Storm" was found dead Saturday in the zoo's holding facilities. The cause of death hasn't been determined. Keepers said the sea lion was behaving normally and showed no signs of illness less than an hour earlier.

A necropsy, or animal autopsy, was performed Saturday.  Zoo Chief Veterinarian Dr. Mike Loomis said results proved inconclusive. Blood and tissue samples have been sent to outside laboratories for further testing, and Loomis said results could take several weeks.

Storm was one of two sea lions that arrived in Asheboro in early November after being rescued by Sea World of San Diego in June 2012. Both animals had been abandoned or lost their mothers.