Police in Thailand have issued an arrest warrant for an "unidentified foreign man" seen leaving a bag minutes before a deadly bombing at a Bangkok shrine.
Police also released a sketch of the man they believe carried out Monday's bombing and offered a 1 million baht (£18,000) reward for help leading to his arrest. But apart from the rough portrait, authorities had few solid leads.
At a news conference, the national police chief expressed uncertainty about the man's origin. Somyot Poompanmoung said the suspect "looks like a foreigner" but "might have been in a disguise and wearing a fake nose" to conceal his identity.
Two days after the attack, which authorities have called the worst in Thai history, the open-air Erawan Shrine reopened to the public.
No one has claimed responsibility for the blast that left 20 people dead and more than 120 injured at one of the capital's busiest intersections during evening rush hour.
A grainy security video shows the man, wearing a yellow T-shirt and shorts, sitting on a bench at the shrine, taking off a black backpack and leaving it behind as he stands up and then walks away. Time stamps on the video show he left the shrine 15 minutes before the explosion, which struck just before 7pm.
"If citizens or anyone can give us information or clues that lead to the arrest of this man, I have set a reward of 1 million baht," Mr Somyot said, adding that police believe the bomber worked with accomplices.
"He didn't do it alone, for sure. It's a network," Mr Somyot said. Police spokesman Lt Gen Prawut Thavornsiri said the security video appears to show two possible accomplices standing in front of the man who are also considered suspects.
Police composed the sketch based on the video and a description provided by a motorcycle taxi driver believed to have given him a ride on Monday night.
The sketch shows a young man in glasses with bushy, dark hair that is cropped at the sides. The warrant describes him as tall, with a pointed nose and thick lips. He faces six charges including conspiring to commit premeditated murder and conspiring to commit a bombing that resulted in death and severe injuries.
The attack has raised concerns about safety in a city that draws millions of tourists.
Prime Minister Prayuth Chan-ocha "is worried about the security of people and tourists in Thailand," the police chief said.
Mr Prayuth has called the attack "the worst incident that has ever happened in Thailand" and vowed to track down those responsible.
The Erawan Shrine is a revered spot among Thais and tourists that transcends religion. It is dedicated to the Hindu god Brahma, but is extremely popular among Thailand's Buddhists as well as Chinese tourists.