Trayvon Martin Case: Rallies Across US Demand Justice

Cries of "no justice, no peace" will be heard as thousands of people across the country are expected to participate in rallies demanding justice for slain teenager Trayvon Martin.

George Zimmerman, the volunteer neighborhood watch captain who claimed he shot Martin in self defense on Feb. 26, has been in hiding ever since demands for his arrest and threats against his life, including a $10,000 bounty for his capture from the New Black Panther Party, were issued.

The Florida rally will end today at the Sanford, Fla., police station- the same place Zimmerman was questioned and released on the night of the shooting.

In surveillance video, which was first obtained exclusively by ABC News,  Zimmerman can be seen arriving in a police cruiser. As he exits the car, his hands are cuffed behind his back. Zimmerman is frisked and then led down a series of hallways, still cuffed.

In the video there are no visible signs of the bloody nose, and gash he told police he received in his confrontation with Martin.

Trayvon Martin Case: Timeline of Events

The brothers of Martin and Zimmerman have publicly defended their loved ones.

"I kind of still don't believe it, which is why it's not easy for me to talk about him, because I just think he's coming back," Jahvaris Fulton told CBS.

Zimmerman's brother, Robert, told  CNN's Piers Morgan this week he believed medical records would corroborate his brother's claims.

"We're confident the medical records are going to explain all of George's medical history both how he was treated at the scene and how he was not," he said.

The uproar has crossed into social media, where the account @KillZimmerman tweets messages calling for his death.

"don't get me wrong I would be happy if he go to jail but I rather see a [expletive] shoot him in his [expletive] face," one tweet said.