Thai police said on Sunday that one mastermind was behind the recent wave of bomb attacks across the country.
Speaking to reporters, Deputy National Police Chief Pongsapat Pongcharoen said that police have a "clear idea" of who was behind the bomb attacks.
"The events are connected, carefully planned and carried out across many areas and masterminded by one individual," he said without elaborating on who the individual was or their motive.
The attacks on tourist destinations and official buildings across five provinces on Thursday and Friday left four people dead and more than 30 injured.
At least 10 foreigners were among the casualties.
Police released a sketch late Saturday of an individual believed to be part of the network responsible for the bombing.
Authorities also received an arrest warrant for an arsonist that set fire to a department store around the same time as the bombings. Pongsapat said that the two events were connected.
National Police Chief Chakthip Chaijinda say the bombings may have been carried out by opponents of a military-drafted constitution, which was approved in a referendum last week.
The two main political parties, both of which campaigned against the constitution, have condemned the attacks as reprehensible and called for a speedy investigation.