Police are confident in their case against Praween Chanklai, aka "Kamnan Nok", a key suspect in the killing of a highway police officer that could lead to his death sentence, said Central Investigation Bureau (CIB) chief Pol Lt Gen Jirabhop Bhuridej.
The evidence can prove the suspect ordered the killing of Pol Maj Sivakorn Saibua even though some files from surveillance cameras have yet to be recovered, he said.
There were 15 security cameras installed at Mr Praween's house and after the shooting, in which Pol Maj Sivakorn was killed and Pol Lt Col Wasin Pandee, another highway police officer, sustained injuries, two CCTV servers were removed and dumped into a canal.
Once the servers were retrieved, forensic police salvaged files from 13 security cameras.
"The evidence we have points to Mr Praween as the mastermind. Witness statements, circumstantial evidence like the gun, the destruction of evidence and the motive are key components we have to get him the death sentence," he said.
Pol Lt Gen Jirabhop said police will gather as much as evidence as they can to make a watertight case because the suspect and his accomplices have no respect for the law.
He said investigators are also speeding up a probe into Mr Praween's businesses to determine the origins of his assets and whether he was involved in price rigging or if he evaded taxes.
The CIB commissioner ordered police to gather information about influential figures in Nakhon Pathom for a planned crackdown to root out mafia-like gangs.
On Friday night, Pol Gen Surachate Hakparn, deputy national police chief, released CCTV images prior to the shooting and after the shooting.
"Most police at the party were armed but didn't try to intervene. Some aided the culprits and some senior officers fled the scene," said Pol Gen Surachate.
He said the motive was clear -- the suspect held a grudge.
On the last two security cameras, one stopped working on Aug 23 and the other was turned off at 10.16am on the day of the shooting.