Police investigating the Ramkhamhaeng bomb blast on Sunday are focusing on the possibility that the attack was politically motivated.
Police officers stand outside Government House yesterday. In the wake of the bomb blast in the Ramkhamhaeng area on Sunday, Government House has asked for the speedy replacement of officers who have been transferred after getting promoted. CHANAT KATANYU
A police source said Metropolitan Police Division 4 has raised two possible motives _ one political, and another arising from possible conflicts involving the owner of a beauty salon which was most damaged in the explosion.
Investigators believe the bomber intended to imitate the bomb assembly style commonly found in attacks in the deep South, the source said.
Nonetheless, the source said authorities have ruled out a southern link to the Bangkok blast, which wounded seven people, because materials used in the bomb and its method of detonation were different to those used in the South.
Army chief Prayuth Chan-ocha said the attack, near Ramkhamhaeng Soi 43/1, was not linked to the unrest, saying military intelligence showed no connection between the Bangkok bomb and the southern violence.
However, the source said investigators believe the bomber made his explosive as close to the southern style as possible to stir up fear and chaos in the capital, which suggested a political motive.
In investigating the personal conflict motive, investigators are conducting background checks on the owner of the blast-damaged August beauty salon, the source said. They want to know if he had any known conflicts.
Investigators have established that a military chief of staff had formerly been involved in the management of the market area near the bomb site, but it is not known if this had any connection to the attack, the source said.
Investigators had found that the lid of a milk can used in assembling the bomb bore a serial number which they believe will lead to more clues as to where the material came from, the source said. However, the investigators had not found the bomb's timer.
Deputy Prime Minister Chalerm Yubamrung said he received a report there had been attempts to discredit a business operator in the Ramkhamhaeng area and he had passed the report to police.
In the wake of the bombing, Pol Maj Gen Thawach Boonfueang, deputy secretary-general to the prime minister, said Government House had requested more police to guard the venue.
There are fewer police at Government House since a number of them moved to other areas after being promoted and were not replaced.
Wisut Chainaroon, the second deputy House speaker, said officers at parliament had strengthened security including conducting more thorough searches of visitors.