Thai police say they have questioned and freed one man who handed himself in after being seen on CCTV at the Bangkok shrine moments before a deadly bomb blast, but the prime suspect remains at large.
A Thai man wanted for questioning after he was seen on security camera footage "met police and was released", national police spokesman Prawut Thavornsiri told reporters on Thursday (local time), adding a second man from China in the same shot had already left the country - but neither were "likely involved".
The main suspect, believed to be a foreigner in a yellow shirt seen depositing a backpack at the scene was still at large, he added.
The two men - the Thai in a red shirt, and the Chinese in white - were initially believed to be possible accomplices of the suspected bomber.
They were seen standing in front of the lead suspect as he took a backpack off and placed it under a bench. They then left the crowed shrine in central Bangkok.
Moments later the bomb exploded killing at least 20 people, mainly foreigners, wounding scores more and sparking a manhunt for the bomber.
"The Thai man is from Chiang Mai," Prawut said, explaining he had taken the Chinese man to the Erawan shrine on behalf of a mutual friend.
The Chinese man returned home a day after the bomb.
Thai authorities have given conflicting and contradictory snippets of information on their quest for the bomber.
But they say they are still confident a bespectacled man in the yellow shirt, described in his arrest warrant as a foreigner is the prime suspect.