Police have charged the alleged mastermind of the Monday-night, execution-style murder of an opposition activist and ruled out any political motives behind the killing.

Cambodia National Rescue Party activist Sann Soeun was shot in the back of the head while reaching for a customer’s change at his Treng Trayoeng commune grocery shop in Kampong Speu province’s Phnom Srouch district, according to police.

The timing of the murder, coming soon after an election that Soeun had campaigned strongly in, fuelled speculation he had been killed due to his party affiliation.

But Som Dara, deputy chief of Kampong Speu police’s justice department, said yesterday that Cambodian-Australian Ouk Run, 51, had confessed to hiring two assassins to shoot Soeun over a land dispute.

“The suspect and the victim are related to each other because the victim was the father-in-law of Ouk Vy, who is the suspect’s brother,” he said, explaining that the brothers had bought five hectares of land from Soeun, which he had refused to hand over after receiving $3,000. “Therefore, this murder is not involved with political stuff,” he said.

A few hours after Soeun was shot, police arrested the alleged trigger man, Choung Vannak, and his alleged accomplice, former kickboxing star Try Kunthor, after the pair fled to Kampot province.

“The three suspects have been charged with intentional murder with serious [potential] punishment,” Dara said.

All three have now confessed and will be sent to court after police had finished questioning them, he added.

On Wednesday the CNRP’s deputy president Kem Sokha attended Soeun’s funeral.

CNRP Kampong Speu province lawmaker-in-waiting, Nuth Rumduol, said that, overall, he was pleased with the efforts police had made to investigate the murder.

“However, some points are suspicious and need to be investigated more thoroughly,” he said.