German police in Hamburg, Schleswig-Holstein, and North Rhine-Westphalia raided several properties belonging to members of the far-left scene arresting one man thought to have been involved in the Hamburg G20 riots last year.

Police in Hamburg say they have arrested a 35-year-old man in the Winterhude district of the city but have so far refused to comment on what he will be charged with, Die Welt reports.

The raids, which occurred Tuesday morning, all focused on far-left extremists who were involved in last year’s “Welcome to Hell” protests that descended into violence last July during the G20 summit and saw hundreds of police officers injured by black-clad Antifa members. Dozens of cars were also set on fire and shops were looted.

Hamburg’s police have also announced four Europe-wide arrest warrants for three men and a woman thought to have been heavily involved in the arson attacks and have requested the public come forward with any information they may have to help identify the suspects.

The operation comes after a series of raids in Italy, Spain, France, and Switzerland earlier this year in May in connection with the riots.

A month after the violence, a report from the German Special Police (SOKO) claimed that far-left extremists had committed as many as 2,000 crimes during the G20.

Police: Alt-Left Extremists Committed over 2,000 Crimes at G20 ‘Welcome to Hell’ Clashes

https://t.co/FdKzNQc0AI — Breitbart London (@BreitbartLondon) August 29, 2017

The report included investigations into 575 individual cases of property damage, 123 cases of arson, 330 cases of assault or bodily injury, 303 cases of breaching the peace, and 45 cases of resisting a police officer. Since then, investigators have expanded the number of cases to over 3,400.

The G20 violence led to the shutting down of one of the German far left’s most influential web portals, the website Linksunten, which was used by anonymous extremists to brag about acts of vandalism and violence as well as to post terror handbooks such as the infamous Prisma booklet that shows activists how to make remote detonated bombs and sabotage infrastructure.

Despite the shut down of Linksunten, Antifa extremists posted a new terror guide earlier this year ahead of a conference being put on by the anti-mass migration Alternative for Germany (AfD) in Augsburg. The so-called guide for “riot tourists” listed a website which also linked to Prisma and other extremist texts.