Serino also told the FBI that he had felt pressure from three officers within the department to charge Zimmerman although he "did not believe he had enough evidence at the time to file charges", and accused one of these officers of being friendly with Martin's father. He also expressed concern to the FBI about possible leaks of evidence to the media from within the department.[140]
The Volusia County medical examiner found that Martin was killed by an injury resulting from a single gunshot to the chest, fired at "intermediate range," between 1 and 18 inches according to a forensic expert.[141][Note 3] An FDLE analysis of Martin's body and clothes described the distance as "a contact shot".[142] The autopsy also found that Martin had one small abrasion on his left ring finger below the knuckle. No other injuries were found on Martin's body at the time of his death.[141] Physicians who reviewed the official autopsy report for the Orlando Sentinel, stated in their opinion that Martin lived anywhere from 20 seconds to several minutes after he was shot, and that Martin likely remained conscious "for a time anyway."[143]
The autopsy report stated that Martin had trace levels of THC, the active ingredient in marijuana, in his blood and urine.[144][145] The toxicology report found the levels to be 1.5 nanograms/ml of THC and 7.3 nanograms/ml of THC-COOH, a metabolite of THC that can stay in the system for weeks after cannabis has been smoked.[144][145] Larry Kobilinsky, a professor of forensic science, stated that the THC amount was so low that it may have been ingested days earlier and played no role in Martin's behavior.[146]