Story highlights Thai politician accidentally shoots former wife and secretary over dinner, police say

Senator Boonsong Kowawisrat was carrying an Uzi sub-machine gun

He has been charged with causing death by negligence

Parliamentary immunity means he cannot be arrested

A Thai politician accidentally shot and killed his former wife and personal secretary with a submachine gun in a restaurant in northern Thailand, local police said Monday.

Senator Boonsong Kowawisarat was dining with Chanakarn Detkard and four others on Sunday when he took out an Uzi 9mm sub-machine gun, police said.

"Senator Boonsong's gun was accidentally fired off while he was trying to keep his pistol into its case. The shot went straight into his secretary who was having dinner," Police Lt. Colonel Choosak Pulsawat told CNN.

The police officer said that Boonsong had been separated from his wife for a while but they were currently living together.

He added that Boonsong had permission to own such a weapon.

Police have initially charged Boonsong with causing death by negligence but he cannot be arrested while the Thai parliament is in session -- unless the parliament rules otherwise.

The Bangkok Post said the charge carries a maximum sentence of 10 years imprisonment and a 20,000 baht fine (US$640).

The newspaper said that Boonsong was so shocked by the shooting that he was unable to take Chanakarn to hospital.

It is not clear why he was armed, why he took the weapon into the restaurant or whether he knew the gun was loaded.

Boonsong is a senator from Mae Hong Song province, which borders Myanmar. The incident took place in Phrae province, also in northern Thailand.

Gun ownership is common in rural Thailand but owners require a permit from the Ministry of the Interior.