Investigators from Provincial Police Region 1, Songkhla police, the Crime Suppression Division and the National Resources and Environmental Crime Division are all involved in the case, reports the Bangkok Post.
Suriya Saengpong, director of the zoological parks organisation, was shot dead at Songkhla Zoo on Saturday by Phuwadol Suwanna, a senior veterinarian in charge of animal health research and conservation at the zoo.
Suriya was investigating the disappearance of two albino barking deer from the zoo - the first in February last year and the second in September.
Phuwadol and three other officials at the zoo were transferred pending the outcome of the investigation. Phuwadol killed himself in his living quarters inside the zoo grounds shortly after shooting Suriya.
Investigators have focused on five issues – the administration of Songkhla Zoo, a missing Macaw, a missing white rhino horn, the missing barking deer, and possible links with the illegal wildlife trade.
A member of the team said that regardless of the outcome of the zoo parks board’s own inquiry, the police investigation would continue, to find out if the shooting had any link with the wildlife trade.
Investigators have learned there was bad blood between Suriya and Phuwadol. The veterinarian had filed a complaint against the zoos chief in 2018 over construction of an ocean park. Suriya had allegedly tried to transfer Mr Phuwadol on several occasions.
This was one possible motive, an investigation source said.
The Department of National Parks, Wildlife and Plant Conservation was also reported to be sending wildlife experts to investigate the disappearance of the two barking deer.