The Israeli military on Sunday said it has opened an investigation into the death of a 22-year-old Palestinian man in the West Bank after a video surfaced appearing to show him being shot in the back.The security-camera video, obtained from a local restaurant in the town of Tulkarem, shows Mohammed Habali walking in an alleyway holding a stick when he is shot from behind and falls down on his face.Several other young males are standing nearby or walking away in the same direction — sometimes looking back — apparently to keep their distance from Israeli troops. No soldiers are seen in the video.Habali's brother, Alaa, said Mohammed had suffered a mental disability and also was physically disabled after breaking his pelvis in a car accident a few years ago. He said the stick his brother carried was used to help him walk.He said Mohammed had worked in a coffee shop and was in the street after closing the restaurant when he saw soldiers in the area.In a statement Sunday, the military confirmed that it was conducting an "operational activity" in Tulkarem last week when dozens of Palestinians began hurling stones at the soldiers. It gave no further details on the operation, but the military often carries out arrest raids in the West Bank.The army said that soldiers responded to the stone throwers with "riot dispersal means" and live fire.It said military police are now investigating the shooting. It gave no details on when the probe would be completed.