BELGIUM -- Just days after police captured the most wanted Paris attacks fugitive in Belgium, a new suspect was named.

New video appears to show Salah Abdeslam making a run for it, even though Belgian security forces were just outside.

He'd done it before, evading police for months before being caught last Friday.

Investigators believe Abdeslam played a central role in the Paris attacks, and had intended to blow himself up, but changed his mind.

Now there's a new suspect: Najim Laachraoui -- who may have been group's bomb-maker. His DNA was found on the explosives used in the gun and suicide attacks in Paris.

His whereabouts are unknown, and prosecutors admitted they aren't close to solving the puzzle.

"We're working on an enormous amount of cases," said Frederic van Hoy. "They're becoming more and more worrying and violent."

Authorities can't explain how Abdeslam was able to disappear for months, only to be captured a few blocks from his home in a Brussels neighborhood.

Interior Minister Jan Jambon told us ISIS is growing more sophisticated.

"They know everything about arms, they know everything about communication techniques. They hide, they have networks. It's professionals against professionals."

But there's another reason Abdeslam may have been able to hide in plain sight, according to Anne Speckard, an expert in violent extremism who's interviewed dozens of Islamic radicals there.

"These are a really brutal, horrible people that went to Paris and gunned people down. So it's not beyond them to also punish anyone that would turn them in."

Prosecutors believe that Abdeslam wasn't just in hiding, but planning further attacks. He's been at a high security prison since Saturday, and his lawyer said he is cooperating with investigators.