A Thai man killed himself after shooting his mistress and her lover when he caught them in bed together.

Phaison, 46, went to visit his girlfriend at her noodle shop in Samut Prakan province on November 2 morning when the incident happened.

However, he was shocked after catching Sudarat, 35, having sex on the second-floor bedroom with a much younger man.

The furious man confronted the two before pulling out his 9mm pistol and shot the woman in the head and died. He also fired several shots on the woman's 25-year-old lover Thanakorn who was hit in the chest and arm and survived.

Thinking that both were already dead, he committed suicide by firing a bullet in his temple which instantly killed him.

Employees said they heard the two fighting before several gunshots were fired so they called the police.

Local police officers arrived at the three-storey building to investigate and helped rush the younger lover to the hospital after he was found still breathing by employees.

The police found the gunner faced-down lying on the bloodied bed next to his dead mistress who fell on the floor.

Police Captain Namasphong Madha said the man had reportedly been paying for the woman's expenses and even built her a noodle shop building, so he was devastated when he found she was also seeing another man.

The cop said: ''Not only was the man younger and more handsome, he had not given the woman any financial support. This caused the killer to become angry.

''He shot them both before committing suicide. However, the younger man has survived.

''The cause of the shooting was jealousy and an emotional issue between the killer and the victim.'';

The younger lover is still being treated at the Rattarin Hospital and has been interviewed by police.