Bangkok  - A Bangkok taxi driver confessed to killing a Thai woman and her 5-year-old son whose body he allegedly chopped up and threw away in garbage bags, media reports said Wednesday.

Siripong Kanchananiwit, 40, surrendered to police Tuesday night after confessing to the state-run Thai News Agency (TNA) that he was responsible for the murder of a boy whose body parts were found in three garbage bags dumped Monday near a Bangkok housing estate.

Siripong also confessed to fatally shooting the boy's mother, identified as Sunan Srisuwan, 38.

The taxi driver claimed he had shot Sunan, with whom he was having an affair; her son, Shaw Makino; and her daughter, Mint, on Monday after the woman insulted his manhood.

"While sitting in my taxi, Sunan made some insulting remark after I failed to follow her demands to kill her Japanese husband," Siripong told TNA. "Her words fuelled my anger. I pulled my pistol to fire shots at her, but she resisted. The four bullets I fired hit Shaw, who died instantly. The bullets also hit Mint."

He then shot Sunan four times, he said.

Lieutenant General Worapong Chewpreecha, metropolitan police chief, said Siripong's claims were "unbelievable" and the case would require further investigation to get at the truth of what happened.

Although convinced that Siripong was the murderer, police said it was hard to believe that the taxi driver had shot three people sitting in his cab and noted that he had fired altogether 14 rounds, meaning he had reloaded his pistol at least once. (dpa)