( CNN ) -- There are dueling narratives in the death of Michael Brown : one says he was holding his hands up in surrender as officer Darren Wilson shot him , and the other says Brown was the aggressor , and Wilson shot as Brown was rushing toward him . Investigators will certainly use high-tech tools to try to get to the truth , but they 'll also use a tool as old as the ancient Greeks : the autopsy . Three autopsies have been done on Brown 's body : one by St. Louis County ; one privately commissioned by the family and one performed Monday by medical examiners from the U.S. military . Detailed findings in the private autopsy -- but not from the other two -- have been released . Based on the circumstances of the case , here are three areas the pathologists likely gave close scrutiny . 1 . Signs of struggle . A friend of Wilson 's called into a St. Louis radio show to say that Brown `` bum rushed '' Wilson and punched him in the face . CNN confirmed that account matches the one Wilson told authorities . But lawyers for the Brown family say the autopsy they commissioned showed no signs of struggle . To look for signs of struggle , pathologists pay special attention to the hands , forearms , feet and shins , looking for signs of abrasions , cuts and bruises . A bruise on the knuckles might indicate the deceased threw a punch , but a bruise would only show up if the punch was pretty hard , according to Dr. Pat Ross , a forensic pathologist in Newberry , South Carolina . And it would be hard to tell whether the bruise was from a fight with Wilson or from something else . `` You really ca n't date a bruise exactly , '' Ross said . `` It may have happened two hours ago or five days ago . '' Pathologists also look for another person 's DNA under the fingernails to help determine whether the deceased person would have scratched the other person during a struggle . 2 . The bullet wound at the top of Brown 's head . The family-commissioned autopsy showed Brown was shot at the top of his head . `` That bullet went in there and came out near the eye area , '' family lawyer Daryl Parks said at a press conference . `` It supports what the witnesses said about him trying to surrender to the officer . His head was in a downward position . '' Ross said it 's possible Brown was surrendering , but he might have been bent over for other reasons , too : he might have been crouching to dodge bullets or he might have been slumped over because he was weak from his wounds , or he might have been making an attempt to rush at Wilson with his head down . Brown was shot at least six times , all to the front of his body , according to the preliminary results of this autopsy . Four bullets went into his right arm , and he was shot twice in the head . 3 . Gunshot residue . Wilson 's friend who called into the radio show said that during the fight inside the officer 's car , both men grabbed for the officer 's gun and it went off . Dr. Michael Baden , the forensic pathologist hired by the Brown family , said there was no gunshot residue on Brown 's skin surface , so at the time the gun went off it was at least a foot or two away . But he added that his team had n't had the opportunity to examine Brown 's clothing , which might have filtered out any gunshot residue . 'An autopsy is a snapshot ' One crucial question an autopsy alone ca n't answer is whether someone was standing still when he was shot or was moving toward the shooter -- and if he was moving at what speed . `` An autopsy is a snapshot , '' said Dr. Eric Mitchell , a forensic pathologist in Kansas City , Kansas . `` And like a snapshot of a ball in midair , you ca n't tell if it 's going up or coming down , or how fast it 's going up or down . '' To answer that question , more details from the investigation are needed . `` It 's uncommon for an autopsy to give you all your answers , '' Mitchell added -- even though crime shows on TV often make it look like autopsies answer all questions with illuminating `` aha '' moments . `` My mother-in law-loves those shows , so I 've been forced to watch them , but that 's just hokum , '' he said . CNN 's John Bonifield and Matthew Stucker contributed to this story .
Three autopsies have been performed in Robert Brown 's death . All look at signs of trauma , wounds and bruises . Autopsies can provide valuable information to investigators . But it 's uncommon for them to provide all the answers , expert ##ly .