Welcome to Pushback. I'm Erin Matte. We have been covering the unfolding scandal at the

Organization for the Prohibition of Chemical Weapons. Two whistleblowers from the OPCW have come

forward to allege that top officials suppressed evidence collected at the scene of an alleged chemical weapons attack

by the Syrian government in the city of Duma in April 2018.

The evidence that was collected, these whistleblowers say, undermined the claim that the

Syrian government carried out a chemical weapons attack, but that evidence was never made

public.

The second whistleblower recently gave testimony at a panel convened by the Courage Foundation,

and I'm joined now by the first journalist to interview that second whistleblower.

Jonathan Steele is a veteran journalist and the former chief foreign correspondent for the Guardian.

Welcome, Jonathan Steele, to pushback. You recently spoke to the second whistleblower.

Talk to us about his position and his main revelations.

Well, he was one of the members of the team of fact-finders called the fact-finding mission, which was sent to Syria after the alleged gas attack.

And he was the man in charge of deciding what samples to pick up from the ground and in related buildings and to decide how to collect them.

And so it was a very senior position.

They checked in two buildings particularly, one which had a cylinder on the roof and the other which had a cylinder on the upper floor of a nearby building just below a hole in the roof.

Now, the rebels claimed that these two cylinders contained chlorine gas.

They've been dropped from Syrian government helicopters.

That's why they were in the position where they were found.

But there was doubt over that.

There was also doubt over the question of the whether there had actually been

any gas at all. The first whistleblower, his evidence was leaked in a report in March this year,

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