So what does it show?
For nearly an hour, the tense stand off between Chamberlain and White Plains police played out.
Chamberlain: "I know I'm going to get hurt, I know that."
Police: "We can't leave until we check you out."
Video from the cops taser gun was recording as the 68-year-old Chamberlain refused to open the door and begged police to leave.
Chamberlain: "I did not call you. Why are you here? Why are you here?"
Police responded to his apartment at 5 a.m. last November because Chamberlain's medical alert was triggered.
Police: "Alarm went off. We need to check you out. You know we aren't going nowhere."
But Chamberlain, who sounded scared, refused to open the door.
Chamberlain: "They're getting ready to kill me or beat me up...They have shotguns, stun guns. They have their glocks out."
The grainy video makes it hard to see, but at one point, Chamberlain shows a butcher knife through a gap in the door.
Police: "Put the knife down and step away from the door. We're going to come in and see you."
Again, Chamberlain refuses to let them in. Eventually, police are able to grab the knife with bolt cutters. The stand off going nowhere, police take the hinges off the door and begin to kick it down.
Chamberlain: "They're taking hinges off the door. They're getting ready to break through."
With the door down, police begin to tase Chamberlain, whom officers said was threatening them with a knife.
Police: Put the knife down.
Chamberlain: Shoot me, come on
The taser video ends, and seconds later, White Plains officer Anthony Carelli shoots and kills Chamberlain. The video and audio made up the crux of the evidence seen by the grand jury, and District Attorney Janet DiFiore said that evidence convinced them police did not use excessive force.
"We did everything we could and should do to put before that grand jury every piece of relevant and admissible evidence," she said.
Chamberlain's son says he's not surprised by the failure to indict.
"If you look at several other incidents where there have been questionable shootings by police officers in Westchester County, the DA has failed to indict any of them," Kenneth Chamberlain, Jr., said.
The family says they will not give up their pursuit of justice, and they plan to ask Attorney General Eric Holder to intervene.
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