One of the largest data leaks in German history, in which private information about 900 politicians was published, was perpetrated by a 20-year-old hacker and student living in his parents' house, authorities said.
The young man, who wasn't identified in line with privacy regulations, had his apartment searched by investigators and has no prior convictions, according to the Frankfurt prosecutors' office.
Officials said he appears to regret his actions.
Authorities said almost 1,000 people were affected by the data breach. In most cases, the information made public was limited to basic contact details, but in up to 60 cases more extensive personal data was published. It was posted via Twitter before Christmas, but only came to most people's attention on Thursday night.
The information appeared to include data on members of all parties in parliament except those from the far-right Alternative for Germany party. Journalists, comedians and activists were also reportedly targeted.
Georg Ungefuk, a spokesperson for the prosecutors' office, said the suspect told investigators that "he acted out of annoyance at public statements by the politicians, journalists and public personalities involved."
The suspect also reportedly told authorities that he acted alone.
The 20-year-old hacker was released on Monday for lack of legal grounds that would justify keeping him in custody, such as being a flight risk.
According to investigators, the suspect also collected publicly available information on the hacking victims – including telephone numbers, addresses, credit card details, photos and communications – and published the material using links posted on Twitter accounts including one with the handle "G0d." That account was suspended on Friday.
The IT security agency, which has been criticized in the wake of the breach, has acknowledged that it was approached by one lawmaker about suspicious activity on his private email and social media accounts in early December, but said it believed at the time his experience was a one-time case.
The Associated Press contributed to this report.