This video catches the moment after a man who attempted to rob somebody with a razor is caught by several members of the public and restrained until the police arrive. Webusers are applauding the gang for their bravery, but our Observer says that by carrying out a citizen arrest, they were taking a huge risk, in more ways than one.

Since it was posted on Monday, the video, apparently shot in Brooklyn, New York, has attracted plenty of congratulatory comments like "we need more people like those citizens". But despite being permitted largely worldwide, and in all states but one (North Carolina) in the US, the scenario illustrates the enormous legal and safety risks that come with a citizen arrest, not to mention the primitive behaviour that emerges with self defence, even from the person filming - allegedly an army lieutenant - whose repeated "faggot", "dickhead" and "fuckface" insults make it hard to take him seriously. Webuser "SoTiredinMI" comments that "this dude with the camera is hilarious [sic] a lot [sic] of bravado almost like he felt the camera was a gun".

"Had [the cameraman] not been there, they would have ripped him up"

Marc MacYoung teaches self-defence after years of firsthand experience following a violent upbringing in LA. He now runs the website "No-Nonsense Self Defence" which promotes preventive rather than physical methods.

This video is an anomaly- a situation like this is extremely rare. It's actually harder to catch someone and detain them than to hurt them. If you're in a group then it might work, but the danger is that the group will become a mob - if one starts, the others join in. I've personally seen people rat-packed. When their arms, ribs and fingers are broken and they start to walk away, someone says ‘wait, he can still walk!' So they break his legs as well. When the cops arrive, everyone's disappeared. That's the most common behaviour. And that's what would have happened to the guy in the video. But in this situation you can see one alpha male dictating the others. You have to notice that he was a lieutenant. He has command. Had he not been there, they would have ripped him up.

I wouldn't recommend trying to catch a criminal. Most people are not willing to match their violence with that of the criminal. There's also the danger of getting in trouble yourself [with the law]. In many states a downward human foot is considered a lethal weapon. When the chef in the video comes out and kicks the guy; that could be considered as attempted murder.

What people have trouble understanding is that they don't realise when the threat has gone away. People get emotional and their "monkey brain" kicks in. If a guy is on the floor or walking away, then that's when it goes from self defence to an attack on your part. That's why attempting self defence gets most people killed or put in jail. It's much better just to take notes, remember details, and act as a witness."

"You step to me, I tell you I’ll take your life"

Posted on LiveLeak 8 Sept 08 by "jdischord". This is not the person who filmed the video; we were unable to locate the origin of the footage.