Three of the four members of the so-called Commando team, allegedly behind the brazen heist of the French crown jewels from the Louvre Museum in Paris are now in custody.

Seven people in all have been arrested after thieves, posing as construction workers, broke through a balcony window at the museum last Sunday morning ransacked two cases of royal jewels

and zipped off into the streets of Paris on motor scooters.

Despite the investigation's progress, there is still no sign of the stolen jewels themselves.

French President Emmanuel Macron has called the robbery an attack on France's history.

So to help make sense of the investigation so far, we are joined now from Amsterdam by art crime investigator Arthur Brand. Arthur, thank you

so much for being here. French authorities say they've got seven in custody, four of whom they say

are actively involved in this heist, but the jewels are still missing.

From your perspective, how would you rate the progress of this investigation?

Well, the French police is doing a great job.

These pieces were stolen not to sell intact because they are known in the whole world.

So their plan is or was to dismantle these crowns,

these necklages and sell the diamonds separately. So it was a race against time for the French

police and within a week they got the first two and now within 10 days they got seven behind bars

and two of them even already admitted that they

were involved, which is a good sign. So I think the French police is doing a very, very good

job. From the details of the crime, does it tell us something about these suspects? I mean,

from your experience, are these professionals? Are they semi-professionals? Are these clever amateurs?

These are professional thieves. You don't wake up in the morning as a normal citizen thinking,

let's become a thief and let's start with a louvre. These guys have done burglars before.

They have been caught before for other burglaries. Then DNA was probably in the systems,

as what we know now. So they were professionals, but they made some mistakes. They left a few

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