The fatal shooting of an unarmed black teenager on Saturday, prompted hundreds of Missouri residents to protest outside Ferguson Police headquarters Sunday.

Chants of "No justice, no peace" and "We want answers" were accompanied by signs that read "Stop police terrorism." As the crowd gathered, St. Louis County Police Chief Jon Belmar detailed how an unnamed officer killed 18-year-old Michael Brown Saturday afternoon.

Belmar says two men-one being Brown- encountered and pushed the officer into a squad car before reaching for the officer's gun. "There was a shooting that occurred where the officer, in fact, shot the subject and they were fatal injuries," Belmar said. He went on to say multiple shell casings were recovered, but couldn't confirm how many times Brown was hit.

The second person has not been arrested or charged but was expected to be interviewed late Sunday.

Witnesses interviewed by a local Fox affiliate painted a different picture. "He ran for his life, they shot him. He fell and put his arms up to let them know he was compliant and that he was unarmed, and they shot him twice more," said Piaget Crenshaw. Desiree Harris, Brown's grandmother, told the Associated Press her grandson was running away. When she got to the scene, Brown was lying on the pavement.

Belmar estimates the victim's body to have landed about 35 feet from the patrol car.

About 60 additional police units were called to the crime scene with dozens staying throughout the night. It was a preventative measure to ensure residents shouting obscenities and threatening to "kill the police" didn't retaliate.

Ferguson is a predominately black suburb about 12 miles north of downtown St. Louis, leading many to believe the officer's action was racially driven. The St. Louis NCAAP launched its own investigation and reached out to the FBI for assistance and Rev. Al Sharpton said he planned to meet with Brown's family Monday or Tuesday.

U.S Department of Justice spokeswoman Dena Iverson said Attorney General Eric Holder has instructed attorneys in the department's civil rights division to monitor developments.

The killing drew comparisons to the 2012 shooting of 17-year-old Trayvon Martin by a Florida neighborhood watch organizer, as well as Eric Garner who died after a New York Police officer subdued him with a banned chokehold.

In a statement posted to their Facebook page, the St. Louis County Police Department said, "We are sorry that a young man lost his life and ask all to give their condolences for the family along with their thoughts and prayers. We are investigating this incident as we would any other shooting. There is no bias or favoritism applied as we are an outside agency and were not involved."