Trayvon Martin Investigator Wanted Manslaughter Charge Prosecutor blocked the charge, fearing not enough evidence for conviction.

SANFORD, Fla. March 27, 2012 -- 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.

The revelation is the latest salvo in a war of leaks meant to bolster each side amid rising tension over the shooting.

Martin's parents, Sybrina Fulton and Tracy Martin, will appear before a House panel today and rallies continue around the country demanding that Zimmermanbe arrested.

About 200 to 250 protesters gathered in front of the Justice Department today to demand the Justice Department to charge Zimmerman with a federal hate crime.

Martin's family attorney confirmed today that the teenager was suspended from his Miami school three times over the past year.

Family attorney Benjamin Crump told ABC News that Martin had been slapped with a 10 day school suspension after a bag with suspected marijuana was found in his backpack.

Last year Martin was suspended for spraying graffiti on school grounds. The Miami Herald reported that the school guard who stopped him searched his backpack and found 12 items of women's jewelry and a flathead screw driver that the guard believed to be a "burglary implement." But Martin was never charged or specifically disciplined for the incident.

Crump alleged that the Sanford police had leaked damaging information about Martin into order to muddy the case, calling it a "conspiracy." Crump called the school disciplinary problems "irrelevant" to the case that "an unarmed 17 year kid was killed."

The case has triggered national interest with pro-Martin rallies in cities from coast to coast. Martin's mother has moved to trademark two popular rallying cries, "I am Trayvon" and "Justice for Trayvon." The family said it does not want want other people printing memorabilia.

"Sybrina Fulton has no desire to profit from her son's death, but wants to protect her son's name legacy," said family representative Ryan Julison.

Martin was shot as he made his way to his father's fiance's house while returning from a convenience store where he bought a pack of Skittles and iced tea. He was followed by Zimmerman who found him suspicious.

At some point, Zimmerman ignored the suggestion from a 911 dispatcher that he stop following Martin, left his truck and went to look for Martin.

At the same time, Martin was on the phone with his girlfriend and complained that someone was following him.

What happened then is not clear. The girlfriend has said that she heard Martin ask someone, "Why are you following me?" before the sounds of a scuffle and the phone was disconnected.

Zimmerman is described as 5-foot-9 and well over 200 pounds while Martin was 6-foot-3 and 150 pounds.

Leaks from the police report detail Zimmerman telling police he was heading back to his truck when Martin knocked him down with a punch to his nose, jumped on him, repeatedly banged his head on the ground, then tried to grab Zimmerman's gun.

In a struggle for Zimmerman's gun, the watchman shot the teenager, Zimmerman told police.