Dutch officials kicked two Russian men out of the Netherlands this spring after officials suspected they were plotting to break into a Swiss lab that was reviewing chemical samples from the Salisbury nerve-agent attack.

When the alleged spies were detained in The Hague, they allegedly had equipment with them that could be used to breach the computer network at Spiez Laboratory, according to reports.

Spiez is believed to be one of the labs that analyzed the chemical used to poison Sergei Skripal—an ex-Russian military official who worked as a double-agent for British intelligence—as well as his daughter on March 4 in Salisbury, England.

The laboratory—which provides “services relating to arms control, protection measures, health and incident management for international organizations, authorities and the general population,” according to its website—previously confirmed British officials’ claim that the Skripals had been attacked with Novichok, a “military-grade” chemical that targets the nervous system, according to The Guardian.

The lab was also reportedly used to analyze samples of chemicals used by President Bashar al-Assad against his own people in Syria. As well as being named by Britain as “ultimately responsible” for the Salisbury chemical-weapons attack, President Putin has been a powerful ally and defender of Assad despite his use of the banned weapons.

Two Russian men—named as GRU officers by Britain—who were caught on CCTV camera traveling to Salisbury to carry out the attack were also known to have visited Switzerland several times in the recent past, but it was a different pair apprehended over the latest alleged lab plot.

Alexander Petrov and Ruslan Boshirov appeared on the Kremlin’s propaganda TV network RT on Thursday to offer up an ill-conceived and laughably implausible explanation for their trip to England. They claimed they had simply gone to Salisbury—on two separate occasions during three days in the country—because they had been told of the wonders of Salisbury Cathedral.

The latest coverup attempt to be exposed was allegedly far more complex. According to Swiss officials, the lab was hit by Kremlin-linked hackers in June, as well as the effort by the two suspected Russian spies earlier in the year.

The men were arrested in an operation that involved Dutch, Swiss, and British intel agencies, an official confirmed to The Daily Beast.

Swiss intel spokeswoman Isabelle Graber said in an email to The Daily Beast that “the Swiss authorities are aware of the case of Russian spies discovered in The Hague and expelled from the same place.”

“The Swiss Federal Intelligence Service (FIS) participated actively in this operation together with its Dutch and British partners,” Graber also wrote. “The FIS has thus contributed to the prevention of illegal actions against a critical Swiss infrastructure.”

“We had several indications that there were some hacking attempts during the last few months,” Andreas Bucher, a Spiez spokesman told Bloomberg News. “But we were not compromised.”