Story highlights Report: 56% of Republicans and 25% of Democrats say there is too much Martin coverage

Considerably more whites than blacks say the same thing, according to the study

A friend of George Zimmerman defends the neighborhood watch volunteer

Rallies nationwide have called for Zimmerman's arrest

While the story behind Trayvon Martin's shooting death continues to grab headlines, interest in the case is sharply divided along partisan and racial lines, according to a new study by Pew Research Center.

Far more Republicans (56%) than Democrats (25%) say there has been too much coverage of Martin's death, according to Pew, which surveyed a "nationally representative sample of 1,000 adults" last Thursday through Sunday about top new stories.

In addition, 43% of whites said the story has garnered too much coverage, compared with just 16% of blacks, Pew said.

Martin's death fractured not just public interest opinions; it also continues to divide supporters of the slain Florida teen and those of George Zimmerman, the man who admitted killing the 17-year-old but claims he did so in self-defense.

Rallies nationwide have called for Zimmerman's arrest, decrying the Sanford Police Department's handling of the case.

JUST WATCHED Zimmerman attorneys say media unfair Replay More Videos ... MUST WATCH Zimmerman attorneys say media unfair 01:51

JUST WATCHED Trayvon Martin's last minutes Replay More Videos ... MUST WATCH Trayvon Martin's last minutes 06:18

JUST WATCHED Taaffe: Zimmerman welts 'clear' on tape Replay More Videos ... MUST WATCH Taaffe: Zimmerman welts 'clear' on tape 03:04

JUST WATCHED Taaffe: Martin shooting 'a perfect storm' Replay More Videos ... MUST WATCH Taaffe: Martin shooting 'a perfect storm' 01:40

On Tuesday, Martin family attorney Jasmine Rand insisted again that a former prosecutor in the case, State Attorney Norm Wolfinger, met with the now sidelined Sanford police Chief Bill Lee the night of the killing and overruled a police detective urging that Zimmerman be arrested.

Rand said the family's legal team has multiple, credible sources who say Wolfinger and Lee met that night. She declined to elaborate.

FBI agents were in Sanford on Tuesday, continuing their interviews in a civil rights investigation. Martin family supporters say the situation is a clear-cut case of racial profiling leading to an unjust killing.

On Monday, agents interviewed Martin's girlfriend, the 16-year-old girl who, phone records show, was on the line with him shortly before the fatal confrontation, Martin family attorney Daryl Parks confirmed Tuesday.

Martin's family and supporters say Zimmerman, who is Hispanic, profiled Martin, who was black, as "suspicious" and ignored a police dispatcher's request that he not follow him. Martin had a bag of Skittles and an iced tea at the time of his death.

The 28-year-old neighborhood watch volunteer has said Martin punched him and slammed his head into a sidewalk before the shooting, according to family members and police.

Zimmerman's legal adviser, Craig Sonner, said Tuesday that criminal defense lawyer Hal Uhrig would represent Zimmerman and that Sonner would serve as co-counsel if the case were to proceed. Uhrig spent more than six years with the Gainesville Police Department in Florida before graduating from law school in 1974.

Meanwhile, a friend of Zimmerman's said video of the neighborhood watch volunteer in police custody does seem to show injuries consistent with Zimmerman's report that Martin slammed his head to the concrete after the two exchanged words.

An enhanced copy of the video appears to show a bump, mark or injury on Zimmerman's head more clearly than does another copy of the video previously reviewed by CNN. That video had a grainy quality.

While the video does not appear to show major wounds, Frank Taaffe, Zimmerman's neighbor and friend, said Seminole County paramedics cared for Zimmerman before they released him to police.

"That's why you don't see him like he came out of a 12-round fight like Rocky Balboa against Apollo Creed," Taaffe said.

But Rand, the Martin family attorney, said Tuesday that it doesn't matter what the videotape shows.

"That does not change our position," she said. "Once again, George Zimmerman was the aggressor. He pursued Trayvon in this instance. If he did have any medical injuries, that did not give him the right to use deadly force and shoot and kill Trayvon."

Also Tuesday, Taaffe told CNN that the neighborhood had experienced a spate of burglaries over 15 months, which he said were committed by black men. But Taaffe said Zimmerman was not a racist.

"Young black men were never the topic of discussion," he said. It was that neighborhood homes had been repeatedly burglarized, he said.

Police records didn't appear to support Taaffe's assertion, describing four incidents involving black men. Taaffe declined further comment to CNN.