Thai police on Saturday said they have arrested a man “likely involved” with a deadly bomb attack in Bangkok last week that killed 20 people and wounded scores more.

It is the first arrest in connection with the bombing at the Erawan shrine in the capital’s bustling downtown district last Monday 17 August which killed mostly Asian visitors, in Thailand’s worst single mass-casualty attack.

“We have detained one person,” deputy national police chief General Chaktip Chaijinda told reporters in a live televised broadcast on Saturday afternoon.

“We have found components of bomb-making materials in his apartment and I am confident that he is likely involved with the bomb attack,” he said on broadcaster T News.

Police had been searching for a prime suspect, described as a foreign man, who was captured wearing a yellow t-shirt on security cameras leaving a bag at the shrine moments before the blast.

But on Saturday Chaktip said it was “not yet clear” whether the man now detained is the same as the one in these images.

“We found dozens of passports inside his room, we have to check which nationalities they belong to,” he said on the televised broadcast.