BANGKOK - The investigation into a deadly bombing in Bangkok's tourist heartland is led by a US-trained officer with close ties to Thailand's powerful military, who oversaw a high-profile tourist murder case in which the conduct of Thai police was questioned.
Chakthip Chaijinda was chosen as the country's next police chief on Aug. 14, just three days before a blast tore through the crowded Erawan Shrine in the Thai capital, killing 20 people, mostly foreigners. The current chief retires next month.
Meanwhile, Chakthip is running an investigation which, four days after the Erawan blast, seems no closer to determining who attacked the shrine and why.
The prime suspect is an unidentified young man spotted on CCTV apparently leaving a backpack at the scene.
But police and military have issued confusing and sometimes contradictory statements about the suspect's appearance, the number of accomplices he may have had and the likelihood of foreign involvement.
As deputy police chief, Chakthip has been the public face of other tourism-related cases in which concerns have been raised about the professionalism of the Thai police.
They include the murder of two British backpackers on the island of Koh Tao in September 2014. Two migrant workers from Myanmar are now on trial amid allegations that police failed to properly seal off the crime scene - a criticism also levelled after Monday's shrine blast - and bungled DNA evidence.
Police have defended their handling of the Koh Tao killings probe and say they have a watertight case.
Chakthip, 55, declined a Reuters request to be interviewed for this story, saying he was too busy.
A Western diplomat in Bangkok described Chakthip as a "straight shooter" who can cut through red tape.
"He's known to be organised and a decent investigator," said the diplomat, who requested anonymity.
Thailand's military seized power in May 2014 and launched a purge of officials deemed loyal to deposed Prime Minister Yingluck Shinawatra and her brother Thaksin.
Within days, Chakthip was made acting commissioner of the Metropolitan Police Bureau, replacing a Thaksin ally.
According to Thai media reports, his recent appointment as police chief was backed by Defence Minister General Prawit Wongsuwan, one of the country's most powerful men.
"The military trusts him," said the Western diplomat. "Good or bad, he's their man."
There have long been tensions between Thailand's military and police. That turmoil has been fuelled by a power struggle between a royalist establishment, which is backed by the military, and the political machine of Thaksin, a former police officer with residual support in the force.
Chakthip investigated two bombing incidents earlier this year that wounded a total of nine people in Bangkok and on the resort island of Koh Samui, but "never produced clear findings", said Paul Chambers, a security expert at the Institute of South East Asian Affairs in Chiang Mai.
Those two incidents and the shrine bombing "could be linked and associated with security officials disgruntled at the junta's leadership", said Chambers.
Asked whether security officials might have been involved in the blasts, junta spokesman Winthai Suvaree said: "I don't think anyone thinks this. Please ask someone else."
Chakthip received post-blast training at the US-funded International Law Enforcement Academy in Bangkok in 2003 and later attended a course at the FBI Academy in Quantico, Virginia.
"Terrorism and bombings are the biggest challenges that come with the job title," said Chakthip in a 2011 interview published on a US State Department website.
"There are lots of techniques used by the terrorists and they keep changing, challenging the authorities with new tricks, trying to stay ahead of law enforcement."