George Zimmerman's lawyer has signaled that he may seek a dismissal of the second-degree murder charges against his client under Florida's Stand Your Ground Law. NBC's Michael Isikoff reports. 
 
 Florida teenager Trayvon Martin died from a single gunshot wound to the chest fired from “intermediate range,” according to an autopsy report reviewed Wednesday by NBC News. 
 
 The official report, prepared by the medical examiner in Volusia County, Fla., also found that the 17-year-old Martin had one other fresh injury – a small abrasion, no more than a quarter-inch in size – on his left ring finger below the knuckle. 
 
 Separately, a medical report on Martin’s alleged killer, 28-year-old George Zimmerman, prepared by his personal physician the day after Martin’s shooting in Sanford, Fla., on Feb. 26, found that the Neighborhood Watch volunteer suffered a likely broken nose, swelling, two black eyes and cuts to the scalp. That report, first reported Tuesday by ABC News, also was reviewed by NBC News. 
 
 Both documents are part of a mountain of evidence – up to 300 pages and 67 CDs of witness statements, surveillance videos and other material-- expected to be made public soon in connection with the second-degree murder case against Zimmerman. 
 
 Zimmerman allegedly shot Martin during a confrontation inside the gated community in Sanford where Zimmerman was a neighborhood volunteer and where Martin was visiting his father’s fiancée. 
 
 After first reporting a suspicious person in the neighborhood in a phone call to Sanford police, Zimmerman followed the teenager before a fatal confrontation that remains shrouded in mystery. 
 
 Related coverage: 
 
 NYT: Police missteps shadow Trayvon Martin case 
 
 Physician: Zimmerman had broken nose, black eyes 
 
 Key events in the Trayvon Martin case 
 
 When police arrived at the scene to find Martin dead on the sidewalk, Zimmerman claimed he shot the teen in self-defense. Zimmerman was treated at the scene for cuts and a bloody nose, then questioned by police for hours before being released without being arrested. Authorities said at the time that they had no evidence challenging Zimmerman's account and that his conduct appeared to be justified under Florida's so-called Stand Your Ground law. 
 
 But after questions about possible racial motivation for the slaying – Martin was black; Zimmerman is a white man of Hispanic heritage – a special prosecutor took over the case and, on April 11, Zimmerman was charged with second-degree murder. He was released on April 23 on a $150,000 bond and has been out of the public eye since then. 
 
 NBC News National Investigative Correspondent Michael Isikoff and msnbc.com's Mike Brunker contributed to this report. 
 
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 (CBS News) SANFORD, Fla., - The trial of George Zimmerman, the neighborhood watch volunteer charged with murdering Trayvon Martin is still months away, but the investigation continues. 
 
 CBS News correspondent Mark Strassmann has come up with new information about what happened that February night when Zimmerman shot the unarmed teenager in a gated community in Sanford, Florida. 
 
 At the heart of this case is what happened of the course of 90 seconds: from the moment Zimmerman hung up with a non-emergency dispatcher -- to the first 911 call from a neighbor. 
 
 Wednesday new details emerged from sources close to the investigation. A responder at the crime scene told CBS News that he and others saw wounds on the knuckles of one of Martin's hands as he lay dead on this lawn, suggesting Martin had thrown a punch. 
 
 Zimmerman told police he fired the shot at point blank range while on his back, as the 17-year-old straddled him. 
 
 He also told investigators Martin did not die immediately but mumbled either "it's over" or "you got me." 
 
 Special prosecutor Angela Corey's team has built a murder case against Zimmerman on evidence not available to the original state attorney or Sanford police - information that includes the autopsy report on Martin. 
 
 State crime lab analysis of his clothes, including gun powder residue that could indicate the distance between of the men. 
 
 Cell phone records from Zimmerman that include text messages he sent up to one month after the shooting 
 
 There are also two surveillance videos, one from the 7-11 where Martin bought Skittles and an ice tea, the other from the clubhouse in the gated subdivision where Zimmerman shot him. 
 
 The special prosecutor's case also includes Zimmerman's medical report the day after the shooting. It listed a broken nose, two black eyes and a cut in the back of the head. 
 
 A source also told CBS News an unreleased police report noted Zimmerman's sweatshirt had "grass stains, and was wet on the back." 
 
 Details from Trayvon Martin's autopsy show the bullet entered the left side of his chest, and shattered the ventrical, one of his heart's two large chambers but the round did not leave his body. 
 
 The reports also noted the fatal wound's surrounded by a two-by-two inch pattern called stippling, caused by gunpower burns. It suggests Zimmerman fired inches away from the teenager.
– Trayvon Martin was killed by a single gunshot fired from an "intermediate range"—evidence suggests just inches away from the skin—according to an autopsy report reviewed by NBC. George Zimmerman has told investigators that he fired the shot while he was on his back as the teen straddled him, CBS notes. The only other injury the autopsy found on Trayvon was a small abrasion, about a quarter-inch in size, on his left ring finger below the knuckle. Zimmerman had two black eyes and a busted nose the day after the shooting, according to a report from his family doctor. Zimmerman has said Martin attacked him before the shooting.