Wed, Mar 28, 2012 9:55 AM EDT

The lead homicide investigator in the shooting of Trayvon Martin recommended that George Zimmerman be charged with manslaughter the night of the shooting, multiple sources have leaked to 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, ABC News reports.

"The rules of justice in this nation have failed when an innocent teenage boy can be shot to death by a vigilante and no arrest is made for weeks," NAACP President and CEO Benjamin Todd Jealous said in a statement last week.

"But until the perpetrator of this heinous crime is brought to justice, we will not rest."