A man was shot dead while riding home on a motorcycle in Pattani on Friday, while a bomb exploded at a school in a separate incident.
Abdullahma Torlae, 39, was shot dead in tambon Kolam of Yarang district after an unknown number of assailants in a car fired a hail of bullets at him and sped away, police said.
The victim died at the scene.
Ban Sarong police station officers and a forensics team found his body with several bullet wounds to the head and torso. The scene was strewn with spent bullet shells.
Police said the motive could be related to the insurgency or a personal conflict as the victim had just completed a jail term after having been convicted on narcotics and firearms charges.
Meanwhile, a bomb went off at 9am at Tadeeka School in tambon Tha Kam Cham of Pattani's Nong Chik district. No injuries or damage were reported.
Police and a bomb disposal team were investigating the incident.
In Songkhla, Muhammad Mama, a suspected insurgent from Pattani, was arrested and two police officers were wounded in a clash in Ban Khuan Rae, Saba Yoi district on Thursday.
An investigation led to the arrest of four other suspects yesterday. They were identified as Sunan Awaejoamae, 27, Ullahfah Kaseng, 40, Worayuth Awaejoamae, 19, and Ismael Samae, 52.
On Thursday, about eight suspected insurgents were reportedly lying low in a house at Ban Khuan Rae planning to provoke unrest in the area. While authorities sealed off the site, the suspects opened fire, prompting a gunfight lasting about 20 minutes.
After an hour, Mr Muhammad turned himself in. Another suspect, Mayako Latae, 35, fled on a motorcycle with a Pattani licence plate.
The incident left two officers wounded. Pol Sgt Anat Sookdam, 27, sustained gunshot wounds to his right leg and Pol Snr Sgt Maj Lamet Limthong, 42, sustained a fractured ankle from a bullet. The two officers were later sent to Saba Yoi Hospital.
Police say Mr Muhammad was involved in the murders of butchers Jirasak Weeyaboonyakiat and Kassaya Muenkoto at Na Ket intersection in Pattani on Nov 29.
CCTV footage showed Mr Muhammad on a motorcycle firing at the victims.