Police in London have now named the three men responsible for Saturday’s terror attack, which left seven people dead and dozens more injured.

One of the attackers, Khuram Shazad Butt, was on authorities' radar and even appeared in a 2016 television documentary called "The Jihadis Next Door."

At one point in the documentary Butt was seen among a group of British jihadis praying with a black Islamist flag in London's Regent's Park.

Also, Italian authorities said they warned British authorities about another of the attackers, Youssef Zaghba.

Former CIA officer Mike Baker joined Melissa Francis on "America's News HQ" today to react to how these radical Islamists slipped between the cracks.

Baker explained that with our current laws and methods, it's impossible - and illegal - for law enforcement and intelligence officials to surveil a suspected extremist indefinitely.

"So he's in the documentary? Or so somebody called and he got on the radar screen at some point?" Baker said. "It's not like the movies. They then don't mount 24/7 surveillance on that person ad infinitum, just going on months and months and months."

He explained that the authorities simply can't do open, in-depth, long-lasting investigations without hard evidence.

"We should be more proactive, we should be aggressive. But that requires laws to be revised, and it requires additional resources," Baker said.

"I understand people being perplexed. But if the law enforcement and the intel communities don't have a wider playing field and the laws aren't revised, they can only do so much."

Watch more above.

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