(CNN) -- Darren Wilson was just one of 53 officers in a small-town police department until his encounter with an 18-year-old August 9 on a street in Ferguson, Missouri.
"He was a gentle, quiet man," Police Chief Thomas Jackson said Friday, referring to Wilson. "He was a distinguished officer. He was a gentleman. ... He is, he has been, an excellent officer."
Authorities, citing death threats, had until Friday refused to release Wilson's name after he fatally shot Michael Brown.
A resident of the St. Louis area, Wilson, 28, has been staying at a secure location since the shooting.
It was not known whether Wilson -- an officer for six years, including four in Ferguson -- had been placed on modified assignment. Jackson told reporters the officer had faced no disciplinary action during his time on the job.
Wilson lives in a neighborhood of modest homes about 20 miles from Ferguson. Neighbors, who seemed angry and worried about the sudden attention on their quiet community, were reluctant to talk about Wilson. Several said the officer left his home days ago.
Brown was African-American; Wilson is white.
One of Wilson's friends, Jake Shepard, said he couldn't imagine the officer killing somebody.
"I can say -- without speaking to Darren, without even having heard his statements -- that, at that moment in time, he was scared for his life," Shepard said.
"I am 100% positive of that because I could never imagine him even in that situation -- taking someone's life, let alone taking someone's life with malicious intent. He's just the last person on Earth that you would think to do something like that. It's just shocking.
Shepard said Wilson "has a huge heart" and cares about people.
"He's kind of quiet when you first meet him," Shepard said. "He stays quiet, he's shy. But he would give the shirt off his back for anybody."
The disclosure of the officer's identity was overshadowed by new details from the police implicating Brown as a suspect in a convenience-store robbery that was reported shortly before the shooting.
Family: 'Beyond outraged'; Police chief: Officer is 'devastated'
The claim was immediately greeted with skepticism and anger from some in the community who have accused Ferguson police of attempting a coverup by not releasing details earlier of the shooting or the name of the officer involved.
Attorneys for Brown's family released a statement Friday saying they were "beyond outraged" over the timing of the robbery allegation, and accused the police of blaming the victim.
"There is nothing based on the facts that have been placed before us that can justify the execution style murder of their child by this police officer as he held his hands up," the statement said.
Missouri Gov. Jay Nixon told reporters, "I think the focal point here remains to figure how and why Michael Brown was killed."
The Ferguson police chief, before speaking to reporters, told CNN's Don Lemon that the officer was devastated by what had happened. Jackson described the officer as well-mannered and respectful.
"This is his community," Jackson said. "He never wanted any of this to happen."
Jackson told reporters Friday afternoon that Wilson didn't stop the young man because he was suspected in the recent robbery, but because he was "walking down the middle of the street blocking traffic."
Jackson said the reported "robbery does not relate to the initial contact between the officer and Michael Brown."
The documents said Wilson, who was treated for injuries after the shooting, was in the area of the shooting after leaving a report of a sick person when he spotted Brown. Brown was named in the documents as the suspect in a robbery of a $50 box of cigars.
The suspect roughly handled a clerk trying to stop him before walking out of the store with a box of Swisher Sweets cigars, according to the documents.
A police officer who responded to the robbery said he identified Brown as the robbery suspect by comparing surveillance images of the incident to the body of the slain teen. The images, showing a large man grabbing a smaller man by his shirt, were included with the documents released Friday.
The documents said four to six shots were fired.
Authorities previously had not mentioned reports of a robbery in the area.
Long-simmering tensions between residents, police
Police have said Brown, who was days away from starting college, according to his family, was killed in a struggle for the officer's gun. No one has disputed that Brown was unarmed, but witnesses said he was shot as he tried to distance himself and raised his hands into the air.
Earlier this week, the shooting sparked protests and isolated looting incidents, and Ferguson police responded with rubber bullets and tear gas. Dozens of people were arrested.
Residents complained about long-simmering tensions between the mostly African-American community and predominantly white police force.
Two-thirds of Ferguson's population is black. The police chief is white. Only three African-Americans are on the 53-person police force.
The mayor also is white, and so are five of the six city council members.
CNN's Ed Lavandera contributed to this report.