Munich police say they have broken up a huge burglary clan which they estimate may have been responsible for a fifth of German break-ins.
The criminal gang was compared by police to an octopus with tentacles across Europe and its members were related by blood or marriage.
The investigation began when three women were caught trying to break into a property in Munich in January 2016.
It has led to arrests in Croatia and Spain as well as in Germany.
Reinhold Bergmann, police commissioner for organised burglary, told reporters that the gang could have dozens of other tentacles operating in other countries such as Belgium, France and Italy.
Young women used as 'worker bees'
The three young women originally arrested attracted attention for the skill and speed with which they were carrying out a burglary in the Munich area of Lehel.
They claimed to be teenagers but police discovered they had forged identification papers and were linked to a wider gang originating in Croatia.
Police went on to arrest another 20 young women in Munich, whom they dubbed "worker bees", along with two alleged gang "middle managers" in western Germany and two alleged leaders in Croatia. Another two are on the run.
Arrests have also been reported in Spain.
Mr Bergmann said the group used young women to carry out the burglaries because they were discreet and less likely to face jail.
They were even traded around different parts of the criminal family, which police say has some 500 members and is highly hierarchical.
"They have no choice but to participate," Mr Bergmann said.
It was impossible to estimate the scale of losses sustained by burglary victims, police said, but it was likely to reach millions of euros. Police found alleged gang leaders living in luxury marble-floored villas in Zagreb.
Croatian police have seized jewellery, other valuables and hundreds of thousands of euros in cash and are trying to trace their owners.