Eight arrest warrants were issued Thursday for suspects in the shooting deaths of four civilians in Narathiwat last week.
Internal Security Operations Command (Isoc) Pramote Phrom-in said the manhunt began after forensic results indicated 18 spent 5.56mm cartridges retrieved from the shooting scene in Sukhirin district last week were discharged from five firearms, of which three were allegedly linked to nine previous attacks in the province going back to 2015.
The nine attacks left 16 -- eight officials and eight civilians -- dead and two officials injured in Sukhirin and Chanae districts.
Isoc's move came after information was disseminated on social media claiming the government was the mastermind behind the Sukhirin district attack on June 7 as well as another shooting in Yala's Bannang Sata district on Monday.
Five civilians were killed in Monday's attack in Yala.
In the Yala shooting, spent 5.56mm cartridges were found at the scene.
They were fired from an HK33 assault rifle which was used in nine previous insurgent attacks in Yala in 2014, 2015 and 2017, leaving 14 dead, one of whom was a state official, and 12 officials from state agencies injured.
The slain official was Pol Lt Col Adinan Isamaea, chief of Krong Pinang police station, who was shot dead on July 10, 2014.
In the Monday attack in Yala, an initial probe conducted by security authorities indicated the five civilians killed had no record of security-related offences.
The officials were running checks on the dead civilians after they found two of them had been detained on drugs charges in 2014 and 2016.
According to local officials and accounts from the deceased's families, the five civilians often gathered together to use methamphetamine and drank a cocktail mixed with krathom leaves, often consumed as a mild narcotic.
Col Pramote insisted the forensic evidence collected from the Sukhirin and the Yala crime scenes strongly indicated the attacks were orchestrated by insurgents.
He said the probes which are under way will be widened to track down the suspects involved in the cases in the two locations.
Narathiwat's Sungai Kolok district on Tuesday was delisted from areas under the emergency decree.
Sungai Kolok district is the seventh district in the far South to be removed from the decree coverage.
It is the first Narathiwat district to be delisted. Previously, four districts in Songkhla, Mae Lan district in Pattani and Betong district in Yala were taken off the list.