BANGKOK (Reuters) - Forty-eight hours after a bomb blast tore through a shrine teeming with tourists in central Bangkok, Thai police appear to have few firm clues about who was responsible for the bloodiest attack the city has seen.
Making their job all the harder, crucial forensic evidence may have been lost or compromised in the chaotic aftermath of Monday evening’s blast.
The strongest evidence the police have so far is grainy CCTV footage of a man who left a backpack at the Erawan Shrine shortly before the explosion, which killed 20 people and injured more than 120.
Police on Wednesday issued an arrest warrant for a “foreign” man, apparently basing this only on the fair colour of his skin, but senior officers publicly disagreed over whether or not he was wearing a disguise.
Two other men seen in the CCTV footage are also suspects, police said, without giving details of their appearance.
Police don’t know whether the suspects belonged to a homegrown or foreign militant outfit.
Experts say the unprecedented scale of the attack suggested a possible link to groups such as Islamic State or al-Qaeda, but police told Reuters they hadn’t contacted their foreign counterparts or Interpol for help with their investigation.
Prime Minister Prayuth Chan-ocha bristled when asked if his government, which was installed after a military coup last year, was seeking outside help.
“This incident happened in Thailand. It is Thailand. Why do we want other people to come in and investigate?” the former general told reporters on Wednesday.
A police spokesman gave conflicting information about the bomb’s components, first saying they were sourced in Thailand and then revising his statement to say it was not clear.
The shrine compound was erratically sealed off after the blast and the cordon was crisscrossed by police, soldiers, volunteer medics and journalists even as explosives experts combed the area for clues.
“The first thing you want to do is get control of the scene,” said Sean Doyle, formerly principal scientist at the Forensic Explosives Laboratory, an agency of Britain’s defence ministry. “The last thing you want is people tramping in and out because they can either bring contamination or confusing evidence into the scene and indeed take evidence away from it.”
Doyle added that Thai investigators likely faced pressure from civil authorities to return the area, a huge draw for tourists, to normal.
“They don’t want to negatively impact on tourism,” he said. “Giving a semblance of things being back to normal would be something they’d want to achieve pretty quickly.”
The area around Monday’s blast was swept up and hosed down the following day. The bomb crater was filled in and the shrine reopened on Wednesday.
“We had collected all evidence which is why the crime scene was reopened,” said an explosive ordnance disposal (EOD) expert with the Thai police who asked for his name to be withheld because he wasn’t authorised to talk to the media.
He said EOD post-blast procedures were the same as in other countries, but in Thailand volunteer medics arrived first to collect the bodies. “Sometimes we can’t control this,” he said.
Editing by John Chalmers and Ian Geoghegan