Last month's five-million-baht robbery in Suphan Buri ended with most of the cash recouped in a case with a hidden trick intending to mislead criminal investigators.
Back on Nov 21, a group of armed men made off with about five million baht in cash after they robbed a team delivering cash to the Krungthai Bank ATM at a PTT petrol station on Song Phi Nong-Wat Phai Rong Wua Road in Song Phi Nong district. A police manhunt was launched with 20 detectives deployed to look for the gang.
A crucial piece of evidence collected from the crime scene was a Samsung Hero phone that appeared to slip out of the pocket of one of the robbers.
Leading the investigation was Pol Col Phumin Phumphanmuang, an expert in tracking criminals from their telephone usage.
Scrolling through the phone's call history, he found 22 numbers were on the outgoing call list.
Contact Crime Track: crimetrack@bangkokpost.co.th.
However, the detective found it rather odd that calls made to the 22 numbers weren't answered or had no chance to answer.
The caller had apparently hung up before the calls could be picked up.
Also, some calls were made to people with criminal backgrounds dealing in illicit drugs, which led investigators to initially suspect that the robbery gang might have been connected to a drug trafficking network.
But after conducting an in-depth background check and analysing the available information, including images taken from security cameras at the scene, the police realised they may have been tricked.
The investigators were convinced the gang had dropped the mobile phone intentionally in the hope that police would be busy sorting out the phone information which would stall the case and give them more time to escape, according to Pol Col Phumin.
The police subsequently decided to track the person who bought the phone and the SIM card. As it turned out, the ID card number used to purchase the phone was that of a woman wanted on a drug offence in Suphan Buri.
After checking the woman's personal information, the investigation team found a striking piece of information -- her ID information stored in the Civil Registration database had recently been copied by someone using the Royal Thai Police's computer system that was linked to the Civil Registration database.
The person who copied the woman's information was a police officer at the Ban Bung police station in Chon Buri.
The investigators visited the station and later identified the policeman who allegedly carried out the ID theft as Pol L/C Withoon Phechpankan, an award-winning, young detective.
Investigators say they managed to identify the ATM robbery gang members from questioning Pol L/C Withoon.
They included Chaidech Phechpankan, a younger brother of Pol L/C Withoon; two other men, Somnuek Somsuay and Suchao Chaengdi; and two youths by the names of Toon and Fa.
According to the investigators, Pol L/C Withoon hatched the robbery plot.
He gave his brother 5,000 baht to open a popcorn stall at the Suphan Buri petrol station to observe the ATM cash delivery three days before the robbery.
He also was accused of assisting Mr Suchao in buying the Samsung phone on Nov 6.
Before the phone was to be dropped at the petrol station during the robbery, Pol L/C Withoon had dialled the numbers of people he knew, mostly those he had issues with so they might be treated as suspects by police and get into trouble.
More importantly, it was a tactic to complicate the investigation and mislead police.
The weapons used in the robbery were a 9mm handgun belonging to Mr Chaidech, who wore a bulletproof vest belonging to Pol L/C Withoon in the robbery.
After the robbery, the gang hid the stolen cash in a wooded area just behind the home of Mr Chaidech's wife in Song Phi Nong district.
Police later caught Mr Somnuek, Mr Suchao and Mr Chaidech separately in the province.
Mr Suchao was detained at a house in Song Phi Nong district while Mr Chaidech was arrested at a hotel in the same district.
Following their arrests, police managed to retrieve a total of 4.9 million baht of the stolen money. Only 181,400 baht remains missing.
Pol Col Phumin said Pol L/C Withoon, who won an award from the provincial police for his outstanding investigative work only in October, decided to assist his brother in the robbery plot because he was afraid his brother would end up getting arrested.
The brother committed the crime because he was in dire financial straits.