Someone in law enforcement had a clue:

The lead homicide investigator in the shooting of unarmed teenager Trayvon Martin recommended that neighborhood watch captain George Zimmerman be charged with manslaughter the night of the shooting, multiple sources told ABC News.

But Sanford, Fla., Investigator Chris Serino was instructed to not press charges against Zimmerman because the state attorney’s office headed by Norman Wolfinger determined there wasn’t enough evidence to lead to a conviction, the sources told ABC News.

Police brought Zimmerman into the station for questioning for a few hours on the night of the shooting, said Zimmerman’s attorney, despite his request for medical attention first. Ultimately they had to accept Zimmerman’s claim of self defense. He was never charged with a crime.

Serino filed an affidavit on Feb. 26, the night that Martin was shot and killed by Zimmerman, that stated he was unconvinced Zimmerman’s version of events.

Zimmerman, 28, claimed he shot Martin, 17, in self defense.

One complicating factor in the investigation was that the first detective to interview Zimmerman about the shooting was a narcotics officer rather than a homicide detective.

The State Attorney’s office said only “no comment” when asked about the affidavit today.

Unfortunately we can now expect the Zimmerman defenders to ratchet up their smear campaign on Trayvon Martin to deflect attention from this story. It will also be interesting to see if Florida’s Stand Your Ground law played any role in the decision not to charge Zimmerman.