BERLIN (Reuters) - The West’s knowledge of the secret Russian nerve agent that Britain says was used to poison an ex-spy and his daughter came from a sample obtained by Germany in the 1990s, German media reported on Wednesday.

In a joint report, German newspaper Sueddeutsche Zeitung, the weekly Die Zeit and broadcasters NDR and WDR said Germany’s BND spy agency had secured the sample of the Novichok nerve agent from a Russian scientist.

The sample was analyzed in Sweden and the chemical formula was given to the German government and military, the report cited sources as saying. Western countries used the information to help develop countermeasures.

The story could help shed light on how Britain was able to analyze the poison it says was used to attack former spy Sergei Skripal and his daughter Yulia in England in March.

Britain has blamed Russia for the poisoning. More than 20 Western countries have shown their support for London by expelling Russian diplomats over the affair, the biggest expulsion since the Cold War.

Moscow has denied blame and says London has not been forthcoming about how it investigated the poison.

“The finding about a class of weapons known as Novichok developed in the former Soviet Union largely stems from a previously unknown secret operation of the BND,” a summary of the German news organization’s’ joint report said.

It said it was unclear what had become of the sample, and said the Swedish government had said it could not provide information about the process on short notice.

A spokesman for the German defense ministry said the German military researched how to protect against chemical, biological, radioactive and nuclear weapons materials, in accordance with international law, but could not provide details so as to safeguard members of the military and the German population.

“This includes the question about which substances are being researched and the availability of these materials,” a ministry spokesman said. “As a result, statements and assertions about this are not confirmed, denied or commented on.”

The BND also declined to comment on the report.

The German media report said the BND had informed the U.S. and British intelligence agencies about the case following the analysis, and small amounts of the poison were later produced in several NATO member states to test Western protective gear, testing equipment and antidotes.