Deputy National Police Chief Aek Angsnanond said the hand grenades used at the two rally sites were the same model –RGD-5 Code 48, leading police to believe that the incidents were the work of the same group. The grenades are available along the northern, northeastern and eastern borders.
Police said RGD5 explosives were used during the unrest in Bangkok in 2006, 2010 and 2012.
Gen Aek said police have received tips from many people, and collection of evidence has continued.
A native from Nakhon Si Thammarat was killed and scores injured in the two attacks on anti-government protesters.