Comey called it a “viral video effect,” or “Ferguson effect”: the officers tend to be less aggressive towards a suspect, knowing he or she might be filming them. This “could well be at the heart” of a recent increase in violent crimes, the FBI director added.

“There’s a perception that police are less likely to do the marginal additional policing that suppresses crime — the getting out of your car at two in the morning and saying to a group of guys, ‘Hey, what are you doing here?’” he said.

The FBI director’s claim followed a private briefing on crime rates in the US on Wednesday.

The rates turned out to be on the rise in over 40 cities across the country, and the spike was bigger than last year.

In Chicago, already notorious for its crime rates, murders were up 54 percent from last year, and shootings had increased by 70 percent.

“I don’t know what the answer is, but holy cow, do we have a problem. Something is happening. A whole lot more people are dying this year than last year, and last year than the year before and I don’t know why for sure,” Comey said.

However, he went on to add that “lots and lots of police officers” are avoiding aggressive confrontations with the public due to viral videos.

He first voiced his concerns in October: “I spoke to officers privately who describe being surrounded by young people with mobile phones held high. They said to me, ‘we feel under siege, we don’t feel much like getting out of our cars’.”

However, the Presidential Administration distanced themselves from the FBI director’s remarks, saying they see no evidence supporting the claim.

They declined to comment on Comey’s latest statement.

Former police officer Michael Wood told RT there’s no evidence to back up any connection between the video-taping of police brutality and an increase in the murder rate.

“The ‘Ferguson effect’ is a claim, and it’s a claim completely without merit. It’s completely fabricated,” Wood said.

What’s more, this claim actually offends policemen, he added.

“Maybe he doesn’t see it, but that’s insulting police officers: saying that they are scared, and they don’t know how to do their jobs, and they are so afraid of the camera or somebody being around.

And then it’s telling the public: we’re just wild animals, without the police stamping us on the ground, thing will go crazy.”