Someone appears to have pulled the plug on two CCTV servers at the house of Praween Chanklai, aka “Kamnan Nok”, shortly before the shooting on the night of July 6, suggesting the attack on the two highway police officers was planned, according to Pol Gen Surachate Hakparn, the deputy national police chief.

The two servers from the scene of the shooting were recovered from a canal behind a temple in Ta Kong sub-district of Nakhon Pathom, after they had been dumped there by an employee of Praween in an apparent attempt to destroy evidence relating to the shooting, in which Pol Maj Sivakorn Saibua, a highway police inspector, was killed and another officer was injured.

The files on the two servers were not 100% perfect, suggesting that the device had stopped functioning abruptly due to the power supply being suddenly cut, said Surachate.

Images recovered from another 13 CCTV servers from the house show a security guard holding a handgun during the dinner party on July 6. The security guard was later detained for questioning.

A police source said that the handgun, belonging to a member of the Ta Kong Tambon Administrative Organisation, had been lent to the guard, adding that the TAO member will also be brought in for questioning.