New Ferguson audio, video recordings emerge ahead of grand jury decision

New evidence in Michael Brown's death is creating more tension in Ferguson, Missouri.

New audio recordings of police radio communication before and after the teenager's shooting and video released over the weekend are helping establish a timeline of events, but they fail to answer many crucial questions about what actually occurred.

The video shows Officer Darren Wilson leaving the Ferguson police department hours after he shot Brown. He is seemingly uninjured -- a contradiction to what police originally said, reports CBS News correspondent Michelle Miller.

"If you got a blowout, a fracture to your eye socket, you're not just going to be walking around holding your eye," said Ben Crump, the Brown family's attorney. "We don't see him holding his eye anywhere in that video."

The tape comes as a grand jury considers charges against Wilson, and the decision could come at any time this week.

The encounter between Wilson and Brown took less than 90 seconds, leading to months of protests.

"Ninety seconds, by the way, can be considered a long time or a short time, and it all depends how it went into the grand jury," CBS News legal analyst Rikki Klieman said on "CBS This Morning." "What we have from these audio recordings and the video recording is certainly evidence that could support the Brown family lawyers saying, 'Look, this officer never connected the robbery with Michael Brown.'"

Police radio communications, obtained by the St. Louis Post Dispatch, shed more light on the events of Aug. 9.

"21. Put me on Canfield with two. And send me another car," Wilson could be heard saying.

Wilson first approached Michael Brown shortly after 12:02 p.m. Less than 90 seconds later, Brown was shot and another officer radioed for back-up.

"Get us several more units over here," a police officer said. "There's going to be a problem."

On Sunday, protesters braved the cold and snow on the streets of St. Louis lying down in chalk outlines of bodies and blocking traffic to commemorate 100 days since Brown's death.

"We just wanted them to know that it doesn't matter if the weather is bad, good, ugly. We'll be out here because this means that much to us," protester Rockit Ali said.

The protest is a far cry from the turmoil that shook this city and the nation only months ago, and there's fear that violence could resurface as a grand jury decides whether to indict the officer responsible for shooting the unarmed teen.

"There have been several days of training for police officers at every single level," Missouri State Sen. Maria Chappelle-Nadal said. "We have multiple police jurisdictions that are trying to understand what they can and cannot do."

Ferguson Police Chief Tom Jackson said if Officer Wilson is not indicted by the grand jury, he will be cleared to return to work according to Missouri law. But the Ferguson police department will conduct its own separate investigation and ultimately make the decision on whether Wilson will stay or go.

"This is a long grand jury seating, very, very unusual," Klieman said. "The entire case, like a trial, is being presented to this grand jury, and...this grand jury is going to be empowered in and of itself to make this decision."