
Tosatit Samithamuksik, 48, who worked at an education centre in Krong Pinang, took several bullets at close range in the torso. He died on the way to hospital.
Ridding pillion with Tosatit was his wife, Nithaya Wonglakorn, who escaped unharmed. The two were returning home from the education centre.
The attack followed a weekend of continued violence that saw four people, including a police officer, shot dead in suspected separatist attacks.
Police said a 43-year-old border patrol policeman was shot dead late on Sunday afternoon in Pattani, while a 52-year-old Buddhist woman, and a 49-year-old Muslim man, were killed in fatal drive-by shootings early yesterday in the same province.
Sunday evening also saw a 50-year-old Muslim village leader shot dead by a gunman.
The spate of killings came as southern Thailand began observing Ramadan, the month when the faithful fast from sunrise to sunset.