"PSO Siyaram Singh, who had received serious intestinal injuries in the gun fire, died of multiple organ failure in the wee hours," said Dr Sandeep Dave at Ramkrishna Care hospital.
Singh had received bullet injuries which caused infection in several body parts, he said, adding that ten more injured persons being treated at the hospital are out of danger.
Chhattisgarh Armed Force jawan, Siyaram, a native of Bihar, was paid rich tributes at the 4th battalion Mana camp here today.
Heavily-armed Maoists had ambushed a convoy of Congress leaders at Darbha last Saturday, killing 27 people, including PCC chief Patel, his son Dinesh, senior Congress leader Mahendra Karma and ex-MLA Uday Mudaliyar and injuring 37 others, including former Union minister V C Shukla.
Personal security officer (PSO) of Karma, Siyaram, critically injured in the attack, was airlifted to Raipur for treatment.