Martin FamilyAP Photo; Orange County Jail via Miami Herald/AP Photo

SANFORD, Fla. - New analysis of calls to police made by George Zimmerman, who shot and killed 17-year-old Trayvon Martin, show a man who never offered up race as a descriptor of suspicious people in the neighborhood watch area until being prompted by a dispatcher.  On the calls he made to Sanford, Fla., police he seems reluctant to take initiative in pursuing one suspicious man.

Since August 2011, Zimmerman has called in to a non-emergency police line seven times, according to documents released by the Sanford Police Department. Of those calls, five were made to report a "suspicious person." In the audio released by Seminole County Sheriff's Department, he describes the suspicious characters as black or African-American, though never mentioning race until after he was asked to describe the characters.  These five calls all began similarly, with Zimmerman saying that he was calling as a result of past break-ins or robberies.

Zimmerman appears to be quite business-like in the calls, offering detailed descriptions of what he was seeing in a matter-of-fact manner. On one call he relates details of kids playing in the street, darting by passing cars.

In another call he described two "suspicious" men that he said were loitering, adding that he had "never seen them before." Another described a black male wearing a black leather jacket and hat with ear flaps. Zimmerman said that he had seen the man picking up trash and "didn't know what his deal was." In this call, Zimmerman adds that, "I don't want to approach him personally."

These added details may help Zimmerman as he and his lawyers fight to defend his innocence both in the court of public opinion and any potential trial. The case is under investigation by Florida Fourth Judicial Circuit State Attorney Angela Corey's Office. The Department of Justice has issued its own probe, investigating possible civil rights violations.

As protests continue, portraying the shooting as racially motivated and calling for Zimmerman's immediate arrest, his family and lawyers maintain that he is not a racist. Appearing on Fox's "Sean Hannity Show," Zimmerman's father, Robert Zimmerman, said that his son had never used any racial slurs, even recounting a time when the younger Zimmerman campaigned on behalf of a homeless black man after a white son of a police officer punched him.

But for the family of the slain teenager, they say that the only thing that can begin to alleviate their pain is an arrest. They allege that Zimmerman, his family, police, and local government were all involved in a  cover-up to sweep Martin's death under the rug.

In a letter sent to the Department of Justice earlier this week, the family called for a probe into an alleged meeting with former Police Chief Billy Lee and State Attorney Norm Wolfinger, whose office was previously in charge of the case before Wolfinger recused himself.

The letter refers to a report first reported by ABC News that the lead investigator on the case recommended that Zimmerman be charged with manslaughter, a recommendation that Wolfinger's office did not take.

Wolfinger responded to the family's allegations in this statement released earlier this week: "I am outraged by the outright lies contained in the letter by Benjamin Crump to Deputy Assistant Attorney General Roy Austin dated April 2, 2012.  I encourage the Justice Department to investigate and document that no such meeting or communication occurred. I have been encouraging those spreading the irresponsible rhetoric to stop and allow State Attorney Angela Corey to complete her work.  Another falsehood distributed to the media does nothing to forward that process. "

State Attorney Corey's office has promised a thorough investigation into the shooting, which occurred on February 26, 2012. A grand jury could hear the case on April 10. Corey has said that there is no guarantee that the case will even go before a grand jury and sources within her office tell ABC News that an arrest, if it does occur, will not occur before next week.