German federal police have arrested a man suspected of being responsible for a huge leak of personal details on hundreds of politicians, celebrities and journalists last month.
Sources say the man - a 20-year-old from the western state of Hesse - has given a full confession.
Germany's political establishment has been rocked by the news that private phone numbers, photos and online message transcripts were released online bit by bit on Twitter throughout December.
Contacts, private chats and letters, financial details, addresses and copies of identity cards were exposed in what appeared to be one of Germany's most far-reaching data leaks.
It targeted members of all the country's political parties - except the right-wing party AfD.
The information was released in the style of an advent calendar last month, along with data from celebrities and journalists.