Yala native Mahadi Malee, 26, was arrested at the home of his wife, whom he married only two weeks ago.
It is understood his DNA was found at the scene of the attack in Muang district.
Mahadi, previously detained on suspicions of involvement in the unrest in the deep South, has maintained his innocence.
Officers sent him to be interrogated at the Southern Border Provinces Police Operation Centre’s Pitak Santi Centre in Songkhla, as it is believed he can provide information implicating others in the attack.