Sri Lanka's military said Thursday it has proved conclusively through DNA testing that Tamil Tiger chief Velupillai Prabhakaran was killed last week, after supporters refused to believe a government video showing the leader's dead body.

Military spokesman Brig. Udaya Nanayakkara said lab tests compared the DNA of the man they believed to be Prabhakaran with that of his son, who was also killed in the fighting, and proved that the body was the rebel leader's.

TIMELINE: 25 Years of Civil War in Sri Lanka

The army had determined the son's identity through photographs.

The government declared last week that it won the 25-year civil war against the insurgents and announced it had killed the rebel leader and many of his top commanders. Government television showed Prabhakaran's body with a handkerchief covering a fatal head wound.

But many of his supporters refused to believe the video, and an ethnic Tamil lawmaker demanded that Prabhakaran's death be proven through a DNA test.

According to the United Nations, 80,000 to 100,000 people have been killed in Sri Lanka's civil war and about 280,000 people were displaced and are living in government-run camps.