A leading security expert says the maniac who killed at least 84 people along a crowded boulevard in Nice, France, may be one of a growing group of "bedroom terrorists" — loners whose bloody rampages are triggered by the Islamic State through social media.

And that makes it much harder to track them and prevent their cataclysmic acts of terror, Will Geddes — founder of the IPC Group, a leading threat-management company — told BBC Radio 5 Live.

"The situation we used to have to deal with was where individuals would go to a training camp in Afghanistan or in Pakistan or in Iraq," Geddes explained.

"[Now] these are what I would call the 'bedroom terrorists,' who have been remotely recruited, and thus makes it incredibly difficult for the intelligence agencies to detect. … It's all part of the very clever and insidious means of recruitment that Islamic extremists are currently using.

"They keep the network of those in the know about planning an attack limited, and they're appealing to the disenchanted and even those with mental illness. … That community is much more susceptible to this insidious recruitment remotely."

Authorities say Mohamed Lahouaiej Bouhlel, who they've identified as the mass killer, was not on any terrorist watch and had a criminal record of only petty crimes.

"My speculation … is that compared to the Istanbul airport attack or the Brussels attack or the Paris attack … where there was a larger group of individuals who were highly motivated, well equipped, well-resourced and well planned, that the attack we saw in Nice … was probably a disenchanted individual who was more inspired than they were directly instructed through a chain of command," Geddes said.

"We're seeing a very different model to the hierarchy of Islamic State now than what we conventionally used to see with al-Qaeda, which had very clear routes and channels of communication."

Geddes' company — which specializes in protection from and emergency response to terrorism, kidnapping, extortion, fraud and corruption and other mayhem — draws its employees from former military Special Forces, law enforcement, anti- and counter-terrorism experts and intelligence services.

The BBC 5 Live interview was transcribed by The Independent, which reported it in Friday's editions.

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