BANGKOK — Jirapan Koisap said he only meant to vent his anger at a Muay Thai referee he blamed for a 20,000 baht gambling loss.

But, as it turned out, while he was beating the referee with a wooden stick in front of Lumpinee Boxing Stadium in northern Bangkok on Saturday, a security guard intervened. That’s when Jirapan’s getaway driver shot the guard dead, and both men fled the scene.

Jirapan, 36, was arrested and taken to “re-enact” his crime at the scene Wednesday. He said he didn’t expect the assault to escalate into someone’s death and maintained he targeted the referee out of anger. Police suspect that there might be more to the story.

“I did it only to teach him a lesson,” Jirapan told reporters. He said he believed that the boxer he placed bets on should have won, so he was convinced that the referee, Udom Deekrajang, was paid to rig the match.

According to police, Jirapan and his hired accomplice, who remained unidentified, arrived at the stadium on Saturday and assaulted Udom. When 24-year-old Anucha Pathuma saw what was happening, he tried to break up the fight, only to be shot dead.

Anucha is said to have come from a poor background in Maha Sarakham province. He left behind a wife and a 4-month-old daughter. Anucha’s family said he was planning to move back to work in his hometown so he could be with his spouse and child.

Jirapan was charged with a variety of offenses, including murder, firearms possession and physical assault. His accomplice remains at large.

Bang Khen police station chief Amnart Intarasuan said he doubts Jirapan acted on his own.

“We are not very convinced,” Col. Amnart said by telephone. “The suspect wasn’t an avid gambler. He only played a little and lost a little … it’s incredible that he would go to such lengths to strike someone in the head like this.”

Amnart said police are expanding the investigation because they suspect Jirapan might have been hired by another party to exact revenge on Udom.

“Let’s just put in this way: We believe there might be more perpetrators in this case,” he said.