Russian agents researched fire protocols at a factory owned by a German arms firm shortly before it burst into flames last summer, The Telegraph can reveal.

Western officials have long suspected that the blaze, which broke out in May 2024 at a Berlin factory owned by the Diehl group, was the work of Russian saboteurs trying to disrupt the supply chain of arms deliveries to Ukraine.

But it can now be revealed that suspected Russian agents tried to find out information about fire safety measures around the site in the run-up to the incident.

“There were internet investigations [in Russia] a few weeks before and after the event, on what fire engines they have and what protocols they have,” a European security source with knowledge of the investigation told The Telegraph.

The source noted that the suspects made little effort to cover their tracks online, suggesting that they wanted Western intelligence agencies to know Russia was involved.

“Russians are not as stupid as to leave that breadcrumb trail, sometimes they simply want us to find out they have flexed their muscles. It’s part of the hybrid warfare,” they said.

The source said the investigation, which had not yet found hard proof of Russian sabotage, added that “very smart people are working on the case and figuring it out”.