A forensic analysis by the Royal Thai police links the chain of attacks, which left four people dead and 35 injured last week, to insurgents active in the southern part of the country, the media reported Monday.
"The bombs used in the Phuket, Phang Nga and Surat Thani attacks were related and similar to those found in insurgent attacks in the deep South," said Suchart Theerasawat, assistant national police chief, after a meeting with forensic experts Sunday.
Thai authorities have requested cooperation from Malaysia, where the Samsung mobiles used to remotely detonate the bombs were allegedly acquired, Efe news reported.
The series of attacks on August 11 and 12 began when a bomb exploded at a market in a city in Trang province, leaving a female Thai vendor dead, and seven people injured.
A few hours later, two other bombs went off within 20 minutes of each other in the resort city of Hua Hin, some 200 km southwest of Bangkok.
The series of explosions, totalling 14 bombs, continued till Friday morning, claimed four Thai lives, and left 35 injured, including ten foreigners.
Meanwhile, security agencies have managed to neutralise eight other explosives.