Kosin Rattanawibun is accused of falsifying documents to obtain the release of two white rhino horns from Prince of Songkla University’s Faculty of Science.
Kosin denied falsifying documents or being involved in the theft, which dates back to 2018.
The case is back in the spotlight after a top zoological official was murdered last week while investigating the disappearance of animals from Songkhla Zoo.
Suriya Saengpong, director of Zoological Park Organisation of Thailand, was shot dead during his visit on October 3. The shooter, Phuwadol Suwanna, head of the zoo's conservation department, then killed himself.
The other suspect in the missing rhino horn case has since died.