Bangkok: A week after a deadly bomb tore through central Bangkok, Thailand's police chief on Monday admitted that his force's frantic search for those responsible has been hampered by faulty security cameras.
The trail is growing increasing cold seven days after the bombing, which killed 20 people in the capital's commercial heart, mostly Asian tourists, and wounded scores more.
The main suspect -- an unidentified man in a yellow T-shirt seen on CCTV placing a rucksack under a bench at the Erawan shrine minutes before the blast -- is still on the run with police publicly no nearer to naming him or his motivations.
National police chief Somyot Poompanmoung said his officers were working at "full capacity with no rest".
But he added that the investigation was bedevilled by shortcomings, such as the fact that the majority of the city's security cameras were not working.
"Sometimes there might be 20 CCTV cameras on a road but only five of them work," he told reporters. "Another 15 might be broken for whatever reason."
Police also say they lack modern facial recognition technology to decipher who the bomber is from the grainy security camera footage.
Somyot is under intense pressure from both the public and the ruling junta to catch the perpetrators of an attack that sent shockwaves through the vital tourist sector. It was Thailand's worst single mass-casualty attack.
Police are convinced the main suspect, who has been named in an arrest warrant as foreign, must have had help from a network, likely involving some Thais.
But Somyot said he was no nearer to knowing whether he had fled the country or not.
"I say that I belive he is still in Thailand because I don't have information to confirm otherwise," he said.
Security footage has played a key role in tracking some of the key suspect's movements.
Cameras have picked him up arriving at the shrine via a tuk-tuk (small taxi), leaving the bag and then departing on a motorbike taxi south towards the Silom area of Bangkok.
After that he disappears from view.
Somyot said he was hoping for technical help from other countries which might have computer equipment that can quickly search large amounts of CCTV footage as well as "make the picture more clear".
He said a number of countries had offered help, but some of their equipment did not work with the Thai systems. Other nations had been sent evidence but had yet to get back with their findings.