The gunmen who stormed the offices of a satirical newspaper in Paris Wednesday, killing 12 people, are “very, very professional” fighters who were likely trained overseas to carry out an attack designed to scare journalists and citizens around the world, security experts say.

As French police and special forces launched a Paris-wide manhunt for three suspects who were last seen heading for the northeast end of the city, terror experts observed that the gunmen executed a carefully crafted plan.

Video footage of the assault shows a “shocking” calmness among the attackers, evidence that they have been well-trained and have likely seen battle overseas, according to Derek Humble, Globe Risk International senior operational consultant. 

“These are too professional to be suicide bombers,” Humble told CTV News Channel on Wednesday.

“Suicide bombers are the riff-raff that they pull into the organization and use them as cannon fodder. These guys are very, very professional. They’ve probably been in battle, they’ve probably been under fire. The calmness that they displayed throughout this attack is the shocking thing.”

“That comes with training,” Humble added.

Eyewitnesses reported that the gunmen spoke perfect French, which suggests they may have been born, or at least largely raised, in France.

Therefore terror experts believe they have spent a considerable amount of time training with a radical group overseas, and were then sent home to perpetrate an attack designed to get the world’s attention.

During their attack, the gunmen reportedly claimed to be members of al Qaeda, but the veracity of those claims has not been confirmed.

“People wonder why we’re trying to stop people from going and joining something like ISIS. It’s because, that’s where they get their basic training,” Humble said.

“They don’t care about how violent they are, they’ve seen violence.”

The gunmen may have spent as long as two years with a group overseas before they were ordered home and supplied with weapons, Humble said.

“You’ve got to take the battle to where it’s going to get noticed, which is, in this case, Paris,” he said.

Canadian officials have identified about 100 people who have gone overseas to train with terror groups and then returned to Canada. Terror expert John Thompson says that in European countries such as France, Germany and Great Britain, there are likely “hundreds” of such individuals.

The high-powered weapons the gunmen allegedly used also suggest overseas help, according to Thompson.

While tens of millions of Kalashnikovs were manufactured, “they are hard to acquire in western societies,” he told News Channel.

The fully automatic version is prohibited in Canada and in many European countries, and rare to find in the United States, Thompson said.

‘Kill one, terrify 10,000’

The attack on Charlie Hebdo, a weekly paper focused on political satire, followed the publication of a series of cartoons that have criticized jihadi fighters, the head of the Islamic State terror group, and the Prophet Muhammed.

One of the gunmen could be heard on amateur video yelling that they had avenged the Prophet. “We killed Charlie Hebdo,” a gunman yelled.

The newspaper itself had been threatened, and was firebombed a few years ago. Editor Stephane Charbonnier had been assigned a police bodyguard. The two were among those gunned down in Wednesday’s attack.

Thompson said the killings amounted to “a very deliberate and selected assault on the institution of free speech.

“With terrorism, kill one, terrify 10,000,” Thompson said.

“They were just putting down an intimidation on every journalism outlet in the entire world that if you talk frankly, or even a little bit sarcastically, about things that terrorists hold dear, they will attack you.”

The manhunt

The challenge for law enforcement officials currently hunting down the gunmen is they will likely have supporters in Paris who will hide them until police can hone in on their location.

France has the largest Muslim community in all of Europe, about 5 million people, and tensions have been high in recent years. Muslim communities have decried what they feel are anti-Islam messages coming from the French government. They are also dismayed by France’s ongoing military involvement in the Muslim world, most recently in the coalition airstrike mission against ISIS in Iraq, says security expert Eric Margolis.

“So there’s a lot of gunpowder there,” Margolis told News Channel.

However, even during periods of relative calm, a heavy police presence regularly blankets Paris, and the gunmen will likely be found, he said.

“I think they will be caught (and) they will probably be gunned down too, as we’ve seen on previous occasions,” he said.