The Dutch police allegedly broke into the servers of the chat service EncroChat, which is popular with criminals in January 2019.
According to AD, this is stated in an internal file document.
In July this year, it turned out that the police were able to read conversations on the normally secure EncroChat for a longer period of time, as a result of which dozens of people could be arrested.
Criminals used EncroChat in the hope that the encryption used made eavesdropping impossible.
Police said it had been read into conversations on EncroChat since April.
It now appears that the police already had access to the servers in January 2019.
Since then, administrative information from the chat service itself has been collected by the agents.
According to the document, agents had since also had access to photos, notes and financial data shared by users.
However, that data is encrypted, so that it cannot simply be viewed.
See also: Justice could watch live communication with criminals after cracking EncroChat
'Key possible in telephone data'
The police need the correct keys to make them legible.
The file speculates that those keys may be hidden in obtained telephone data.
If they are found, the police will have more information for possible investigations.
By breaking into EncroChat, the police managed to arrest several people.
8,000 kilos of cocaine, 1,200 kilos of crystal meth, dozens of weapons and 20 million euros in cash were also seized.