Police have broken up a gang who were giving step-by-step bomb tutorials on how to blow up cash machines.
The operation was being run from the Netherlands and led to ATMs being targeted in Germany, culminating in a loss of $2.5 million.
Europe's crime agency Europol led a joint investigation with the Dutch and German authorities to catch the gang.
It led to the arrest of nine people and seven raids in areas around Utrecht, Amsterdam and The Hague.
The investigation was first launched 18 months ago after authorities in Osnabruck, Germany, identified suspicious orders of ATMs from a German company.
Special surveillance measures were put in place, which led the investigators to Utrecht in the Netherlands.
"A 29-year-old individual and his 24-year-old accomplice were running an illegal training centre for ATM attacks," Europol said.
"There, the pair was ordering different models of ATMs and recording tutorials on how to most effectively blow them up."
Police had a breakthrough when one of the gang members accidentally died during a test run.
"The criminals were producing step-by-step tutorials on how to blow up cash machines, and have been linked to at least 15 ATM attacks in Germany," Europol said.
"The cash machines were blown open using homemade explosive devices, posing a serious risk for residents and bystanders.
"During one of the test runs of an explosion, one of the suspects died, with another suspect getting seriously injured."
The investigation culminated in a series of police raids on Tuesday.
Those arrested in the Netherlands now face extradition proceedings to Germany.
Explosive attacks against ATMs are a growing concern, because they often put residents’ and bystanders’ lives in danger," Europol said.
"To prevent and tackle this type of crime, a close co-operation between law enforcement and the ATM industry is paramount.
"In this regard, Europol and the European Crime Prevention Network have worked on a number of recommendations to prevent physical attacks against ATMs."
Latest figures show losses in EU member countries from ATM attacks in 2017 was €30 million ($34.8m).
"Some countries continue to witness a significant number of physical attacks on ATMs, others have experienced a significant increase in the number of these incidents over the past two years," Europol said.
"Not only banks are affected, increasingly ATMs from independent providers are attacked because they are often in more vulnerable premises or locations.
"To set up an efficient set of preventive measures, the installation of a national authority that has the power to impose specific measures for high-risk ATMs, based on a thorough analysis of the situation, is best practice. This approach has been proven effective in France."