A team of CSD police used Line Group _ a popular instant messaging application for iPhone, iPad and Android smartphones _ to help them arrest murder suspect Veerasak Iempongsa.
Mr Veerasak, 39, a native of Trang, was arrested on Oct 8 when a passenger bus he was travelling in stopped on Phetkasem Road in Nakhon Si Thammarat's Thung Song district.
He is wanted by Japanese authorities for the murder of Awaji Megumi, 33. She was killed in her room at the Youkawa Building in Tokyo's Toshima ward on March 14, 1993, when Mr Veerasak worked as a bar host in Shinjuku.
The statute of limitations in his case expires in just five months, on March 14, 2013.
The arrest came after Pol Col Uichi Hara from Tokyo sent a letter to the Foreign Affairs Division, asking the Royal Thai Police Office to follow up on the case.
Tokyo's request landed on the desk of leading crime buster Thinnakorn Rangmat, a superintendent of the CSD's sub-division 6.
In mid-September this year, a team of CSD police travelled to Japan to consult with Japanese police handling the case and gather additional evidence.
On Oct 5, the hunt for Mr Veerasak began, after the Criminal Court issued an arrest warrant.
After receiving a tip that Mr Veerasak was living in his home province of Trang, Pol Col Thinnakorn used the Line Group application to communicate with his team.
"I think Line Group is the best communication channel as it could quickly send messages and video files to all members of the investigation team. More importantly, all team members could send back their views," he said.
After selecting the communication channel, he ordered Trang-based CSD police to stake out the provincial bus terminal.
The suspect's mother worked there and his elder brother worked as a motorcycle taxi driver in the area. Mr Veerasak had no permanent job, but sources said he was a regular customer at a tea shop in the compound of the bus terminal.
After consulting with his team, Pol Col Thinnakorn decided more police from neighbouring Songkhla and Phatthalung province were needed.
"He did not show up that night. At the time, what was most worrying was that we feared he might be aware of our operation," said Pol Col Thinnakorn.
Police tracked his mobile phone use and found he had gone to Tak province, where his elder sister lived, on that night. The location-tracking technology showed he later moved to Nakhon Sawan and down to Bangkok.
The investigation team believed the suspect was on his way to his home province of Trang.
On the morning of Oct 7, it became clear that the suspect was on Rama II road, a main road to the South. The head of the investigation team ordered his team members via Line Group to check which bus the man had boarded.
The suspect had taken a Bangkok-Trang passenger bus, operated by Sri Suthep Tour Co. The bus was due to arrive in Trang that night.
Messages were sent to team members about the suspect's movements. When the bus stopped temporarily in Nakhon Si Thammarat's Thung Song district, police boarded the bus. One officer sat next to the target. The officer started talking to the target to make sure he was the one wanted by Japanese authorities, and immediately handcuffed the suspect.
"We feel proud of our operation. The suspect has been on the run for years and the statute of limitations in his case expires in five months, but we were still able to arrest him," said Pol Col Thinnakorn.