VIDEO: Bangkok bomb suspect held at checkpoint on Cambodian border

Thailand’s prime minister said Tuesday a second foreign man on suspicion of involvement in last month’s deadly shrine bombing has been arrested at a checkpoint on the Cambodian border.

It was the second confirmed arrest in connection with the 17 August blast that tore through a religious shrine in downtown Bangkok and killed 20 people.

When asked whether he is thought to be the person who planted the bomb at the Erawan shrine in Bangkok's busy Chidlom shopping district, he replied, "We are interrogating. He is a main suspect and a foreigner."

The motive for the blast - Thailand's worst single mass-casualty attack - remains shrouded in mystery.