The International Criminal Police Organisation (Interpol), at the request of Thai police, has issued a red notice for the arrest of Pich Kimsrin, a 24-year-old Cambodian man implicated in the fatal shooting of Lim Kimya, a former Cambodian opposition MP.
According to Pol Lt Gen Sayam Boonsom, commissioner of the Metropolitan Police Bureau (MPB), the warrant will allow officers of both Interpol and the Cambodian National Police to track the suspect who is accused of acting as a spotter for the gunman.
At the moment, the MPB is investigating the financial transactions of suspected gunman Ekkalak Phaenoi, who is currently being detained at Bangkok Remand Prison. These records are expected to reveal the identity of the mastermind, said Pol Lt Gen Sayam.
Lim Kimya, 73, arrived in Bangkok by bus from Siem Reap province, Cambodia, on Jan 7.
He was shot dead in front of his wife and brother in Phra Nakorn district.
Mr Ekkalak is accused of carrying out the hit while Mr Pich acted as spotter. They immediately fled the scene.
Mr Ekkalak was arrested on Jan 8 in Battambang, Cambodia, and was brought into custody on Monday, while Mr Pich remains at large.
According to MPB commander Pol Maj Gen Theeradej Thumsuthee, the police arrested another suspect, Chakrit Buakhli, in Chon Buri on Tuesday.
Mr Chakrit, 47, was reported to have helped Mr Ekkalak plan the murder and assist his flight from justice.
The CCTV camera footage revealed that Mr Chakrit drove Mr Ekkalak to Sa Keao after the shooting.
Investigators also found records of a phone conversation between the pair at 1.54 pm on the day of the shooting, four hours before the incident.
Mr Chakrit was charged with assisting in a crime, to which he partially admitted the charges.
According to Pol Maj Gen Theeradej, Mr Chakrit admitted that he was the man in the CCTV footage and that he had known Mr Ekkalak for at least two years during his time as a marine.
He said that he had been working as a driver for travellers crossing Thai-Cambodian border checkpoints in Chanthaburi at the time and was not aware of the crime.