KNOXVILLE, Tenn. (AP) - Officials say they can't pinpoint the type of toxin that killed 34 reptiles at a zoo in Knoxville.

The Knoxville News Sentinel ( ) reports Zoo Knoxville on Friday released necropsy results performed at the University of Tennessee.

University veterinarians determined a combination of swollen blood vessels and changes in the animals' livers and hearts and the sudden deaths of multiple animals pointed to a toxic origin. Zoo president and CEO Lisa New said the specific toxin can't be determined.

The animals found dead in March were mostly snakes. Also killed with a blue-tongued skink and a Gila monster. Eighteen reptiles survived.

New says the zoo will no longer exhibit or house animals in the building where the reptiles died.

Information from: Knoxville News Sentinel,

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