An attorney for Jason Van Dyke, the former Chicago Police Department officer charged with murdering 17-year-old Laquan McDonald, said video of the incident last year isn’t reliable because it "distorts images," Reuters reported. The video, depicting McDonald, who was black, being shot 16 times by Van Dyke, who is white, was made public Tuesday evening after Chicago authorities blocked its release for about a year.

"Video by its nature is two-dimensional. It distorts images. So what appears to be clear on a video sometimes is not always that clear," Reuters quoted lawyer Daniel Herbert as saying. He added that Van Dyke "truly was in fear for his life, as well as the lives of his fellow police officers."

The video does not indicate Van Dyke’s guilt, Herbert said. Van Dyke, who was formally charged Tuesday, could face a minimum of 20 years in prison should he be convicted of first-degree murder.

The video sparked outrage among the public, with demonstrators taking to the streets of Chicago Tuesday night. While some observers expected violence, only five arrests were made. McDonald, who was shot and killed in October 2014, was reported to have been carrying a folding knife, which he refused to drop before the shooting. Authorities also said he had PCP in his system at the time of his death.

Officials in Chicago attempted to block the release of the video by saying doing so would have interfered with a federal investigation the shooting, something a judge last week said wasn’t the case, WMAQ-TV in Chicago reported. McDonald’s shooting came amid a national debate over how police officers operate in their communities.

The deaths of black people at the hands of white police officers and vigilantes has during the past two years and a half years spurred the rise of the social-justice movement Black Lives Matter, which has campaigned to end law-enforcement officer violence against African-Americans.