Two other people seen on the video near the man are also considered suspects in Monday’s deadly bombing, police said late Wednesday.
But police said earlier they had interviewed two motorcycle taxi riders near the shrine, one of whom gave a ride to the suspect.
“We believe there must be people helping him, Thai people”, he added, appearing to rule out the action of a lone wolf attacker.
Thai police issued an arrest warrant yesterday for an “unidentified foreign man” shown in a security video leaving behind a backpack just minutes before the blast, but acknowledged they are unsure of his nationality.
Two Malaysians were confirmed killed, the country’s Foreign Ministry said Tuesday.
He said police believe the bomber had accomplices.
Prawut told reporters Wednesday night that police would continue to scrutinize closed-circuit TV footage of the area from before the blast for clues about suspects.
This August 17 image shows a man wearing a yellow T-shirt near the Erawan Shrine before an explosion occurred in Bangkok, Thailand.
Prime minister Prayut Chan-ocha said the country needed no help from overseas.
The national police chief, Somyot Poompanmoung, has furthermore suggested as many as 10 people could have played a part in the bombing at the Erawan shrine but later conceded the figure was theoretical and did not mean police had 10 suspects.
If the perpetrator is, in fact, a foreigner, it could raise the possibility that global terrorist groups are involved.
There has been no claim of responsibility for the Monday evening attack on Erawan shrine crowded with tourists, which the government has said was created to wreck the economy.
Local authorities have appealed for anyone with information surrounding the alleged bomber to come forward, offering a reward of one million Baht (the national currency) – equivalent to roughly AUD$40,000. “It is likely that many people are involved and had some sort of backing”.
Of the 22 dead, at least 11 were foreigners with visitors from Britain, China, Hong Kong, Indonesia, Singapore and Malaysia among them.
Police officials at the shrine said that the Brahmin statue worshipped at the site had only suffered “minor damage”.
On Tuesday, a small explosive device was thrown at a busy pier on Bangkok’s main river but no-one was hurt.
Thailand has deep political rivalries, besides the decades-long Muslim insurgency.
The suspect in the bomb blast that shook Bangkok on Monday is a foreigner, Thailand police have surmised.