Police have charged politician Chalong Riewraeng with premeditated murder and other serious offences in the shooting death of the Nonthaburi provincial administration chief, and he was denied release on bail by the provincial court on Tuesday.

The Royal Thai Police Office said police at Rattanathibet station officially filed four charges against the former MP before taking him to the Nonthaburi Provincial Court on Tuesday, where he was denied release on bail and his detenton extended.

The charges are: premeditated murder, attempted murder, discharging a firearm in a public place, and illegally carrying a firearm in a public place

Mr Chalong is a former MP for Nonthaburi for several parties at past general elections.

The police statement said the court rejected an application for the suspect's temporary release on bail, which was strongly opposed by police in view of the serious nature of the charges.

Mr Chalong refused to talk to reporters as he was whisked off by a convoy of police vehicles and police commandos, several media outlets reported.

He is charged with shooting dead retired Pol Col Thongchai Yenprasert, president of the Nonthaburi Provincial Administration Organisation, in a parking lot behind the PAO offices in Muang district in Nonthaburi on Monday morning. His driver, known only as Yod, was also wounded.

Thongchai was declared dead at Phranangklao Hospital. The victim was Mr Chalong's long-time friend but had reportedly refused to repay an 11 million baht debt he owed the accused man.

Mr Chalong was also fined 5,000 baht on Tuesday for smoking in a public office in breach of public health regulations, after pictures of him calmly smoking during his interrogation at Rattanathibet police station on Monday went public.

Police have been accused of showing him undue leniency and allowing him special privileges. Critics pointed out he was also not handcuffed, in contravention of normal practice.