Just over two weeks after the fatal shooting, and less than a month before an arrest was made, police in Sanford, Florida, urged prosecutors to take George Zimmerman into custody after arguing his killing of Trayvon Martin was "ultimately avoidable."
This disclosure came out Thursday, part of a wealth of information released that is related to the case, including the medical's examiner's finding that the 17-year-old Martin had traces of drugs in his system in an autopsy conducted hours after his death.
Overall, the newly released material paints the most complete picture yet of how investigators built the case, as well as its complexity. The police perspective was most succinctly stated in a March 13 "capias request" -- a request that someone be taken into custody -- sent to the state's attorney. It speaks to the fact that Zimmerman ignored a police dispatcher's advice not to chase Martin, as well as his communications with Martin prior to the shooting.
New documents shed light on Trayvon Martin killing
"The encounter between George Zimmerman and Trayvon Martin was ultimately avoidable by Zimmerman, if Zimmerman had remained in his vehicle and awaited the arrival of law enforcement, or conversely if he had identified himself to Martin as a concerned citizen and initiated dialog (sic) in an effort to dispel each party's concern" the request said. "There is no indication that Trayvon Martin was involved in any criminal activity."
In his 911 call just before the shooting, Zimmerman had speculated that the teen looked like he was "up to no good or he's on drugs or something."
But Martin's defenders have portrayed Zimmerman as the aggressor, accusing him of profiling the African-American teen. Plus, one expert notes the traces of the marijuana-related substance found in the teen's system, as measured hours after his death, don't necessarily speak to any level of intoxication, while another adds that marijuana use typically doesn't make people prone to aggression.
Martin's blood contained THC, which is the psychoactive ingredient in marijuana, according to autopsy results released Thursday. The autopsy was conducted February 27, the day after the teenager was shot dead.
Toxicology tests found elements of the drug in the teenager's chest blood -- 1.5 nanograms per milliliter of one type (THC), as well as 7.3 nanograms of another type (THC-COOH) -- according to the medical examiner's report. There also was a presumed positive test of cannabinoids in Martin's urine, according to the medical examiner's report. It was not immediately clear how significant these amounts were.
No precise levels on the urine were released.
Dr. Michael Policastro, a toxicologist, cautioned against reading too much into the blood THC levels, adding that one cannot make a direct correlation between those findings and a level of intoxication.
He also noted levels of THC, which can linger in a person's system for days, can spike after death in certain areas of the body because of redistribution.
And Dr. Drew Pinsky, an addiction specialist who hosts a show on CNN's sister network HLN, added that marijuana typically does not make users more aggressive.
Concentrations of THC routinely rise to 100 to 200 ng/ml after marijuana use, though it typically falls to below 5 ng/ml within three hours of it being smoked, according to information on the National Highway Traffic Safety Administration's website.
While some states have zero-tolerance policies for any drug traces for driving while impaired, others set certain benchmarks, the website of California's Department of Alcohol and Drug Programs notes. In Nevada, that equates to 2 ng/ml for THC and 5 ng/ml for THC-COOH, also known as marijuana metabolite. The cutoff level in Ohio is 2 ng/ml for THC and 50 ng/ml for THC-COOH.