Park officials have added animal cruelty to the charges against construction tycoon Premchai Karnasuta, who was arrested early this month for allegedly hunting wildlife in a World Heritage forest.

Pol Maj Gen Krisana Sapdej, deputy commissioner of Provincial Police Region 7, Kanchanaburi, said officials of the Western Thungyai Naresuan Wildlife Sanctuary filed the complaint of animal cruelty on Monday.

As the whereabouts of Mr Premchai, president of Italian-Thai Development Plc, were not known, police would send a summons this week for him to report and acknowledge the new charge, he said.

Cruelty to animals carries a maximum penalty of two years in jail and/or fine of 40,000 baht.

Mr Premchai and three others were arrested on Feb 4 when park rangers found the carcasses of an endangered black Indochinese leopard, a protected Kalij pheasant and a barking deer near his camp in a no-camping area.

Earlier reports said they cooked and ate the meat. Eight bullet holes were later found in the leopard's skin. The suspects were each released on bail of 150,000 baht, with no ban on leaving the country, and ordered to appear in court again on Feb 17.

The 63-year-old construction tycoon and his three companions were already facing nine charges, including unauthorised hunting in a wildlife sanctuary, unauthorised hunting of protected wildlife, unauthorised possession of wildlife carcasses and attempted hunting in a wildlife sanctuary.

On Tuesday officials of the Western Thungyai Naresuan Wildlife Sanctuary handed over a Toyota Land Cruiser to police for further examination. Mr Premchai's group had used it to enter the wildlife sanctuary.

Wildlife protection officials continued to search their illegal campsite for more evidence on Tuesday.