Following an attack on a German member of the European Parliament and a Green Party election worker in the city of Dresden, police have identified all four suspects.
A 17-year-old had previously turned himself in to police on Sunday following the attack on Matthias Ecke, who represents the Social Democrats (SPD) in the European Parliament, during campaign work on Friday evening.
Evidence was seized during house searches and is now being analysed.
The four young men are 17 and 18 years old. It will be some time before the investigation is finalized, the statement by the police and the state's public prosecutor's office said.
The background to the offence is still unclear.
Ecke was brutally beaten by a gang of four assailants on Friday evening while hanging campaign posters in the eastern German city.
He is still in hospital where he underwent surgery on Sunday.
Witnesses described the assailants as dressed in dark clothing and said they seemed to be part of the far-right extremist scene.
Ecke is the SPD's top candidate in the state of Saxony for June's European elections. He has served in the European Parliament since 2022.
Minutes before Ecke was attacked, according to the police, a group of four assailants had also assaulted a 28-year-old Green Party campaign worker while he was putting up posters in the same part of Dresden.
The attacks triggered a debate about the escalation of violence during election campaigns. Several thousand people demonstrated to denounce the attacks and defend Germany's democratic values in Dresden and Berlin on Sunday.
