Aftermath: Security at the precinct drew criticism after the attack, with questions being asked about how an armed member of the public could simply walk in through the front door and begin firing
Detroit police have released harrowing footage of the moment a deranged gunman opened fire on officers from the front desk of their precinct house.
The gunman, 38-year-old Lamar Moore, was wanted for questioning by police and had gone briefly missing before suddenly turning up at the Sixth Precinct house on January 23.
Dramatic surveillance video footage shows two different camera angles of the station - the public area at the front desk, and the section behind the front desk for officers.
Moore can be seen calmly walking into the station and heading toward left-hand side of the front counter.
At the same time seven officers, including the station commander, can be seen going about their usual working day.
Moore is out of frame when he opens fire on the officers, but the results of his deadly actions can be clearly seen - as one officer immediately collapses, others duck for cover and smoke from Moore's gun can be seen billowing in from the right of the frame.
The ensuing gun battle is both terrifying and fascinating, as officers display incredible courage in a bid to face down the gunman.
It is made all the more heroic when, seconds earlier, the officers had no idea they were about be facing death in a firefight at their own station.
It is suggested that Moore decided he was going to commit 'death by cop' suicide, and was prepared to continue his rampage until shot dead.
The precinct commander, a female and male sergeant and another officer suffered wounds in the attack, although all have since been released from hospital.
Detroit Police Chief Ralph Godbee said the video was released to show the 'tremendous acts of heroism' of the Detroit police.
Detailing the injuries sustained by the officers, Chief Godbee said the female sergeant was undoubtedly saved by her bullet-resistant vest, which absorbed a shot to her chest.
Another officer and a male sergeant suffered a grazing wound to the head, while the precinct commander was shot in the back but was still able to return fire.
The shootout only came to an end when Moore dived over the front desk and continued firing at the officers from merely feet away.
Chief Godbee would not reveal how many times Moore was shot, or which officer fired the fatal round, but the footage shows the gunman finally collapsing and dying at the station.
According to Detroit News, Moore was under investigation for allegedly holding a 13-year-old girl as a sex slave.
And authorities told CNN that police had stopped by Moore's home several hours before the shooting, but he wasn't there. The residence had caught fire and was severely damaged. That fire has been ruled as arson.
Questions have been raised about the security of the precinct house, as the lobby was open and unprotected, there were no metal detectors at the entrances and the front desks were not fitted with Plexiglass-type shields.
Chief Godbee said Moore entered the precinct house around 4.20pm through the front door. There was no warning before he opened fire.
Chief Godbee said: 'As you can imagine, utter chaos and pandemonium took place. But through it all, our officers maintained courageous calm. They returned fire. They took cover.
They did all the things that we train them to do under pressure.'
Reacting to criticism about security, Chief Godbee said: 'We have to take a step back and reassess security at each one of our facilities.
It's more than likely that we will be changing a number of things relative to standard operating procedures as to how we screen our public before they come in.'
The department wanted to continue its 'community policing' format at the precincts, he said, but added: 'By the same token, incidents like this... remind us just how vulnerable we all are.'