The police arrested a 28-year-old man in the Kreuzberg district of Berlin on Wednesday morning, where he was caught near two burning motorcycles. A nearby car was also damaged by the fire.
Police said the suspect was known to them, though not as an arsonist, and that there was no indication of a political motive. The man has so far not been charged.
Meanwhile, the arson attacks continued sporadically throughout Tuesday night in Berlin. Unknown people set fire to a car in the Spandau district of Berlin, a car and a truck in Neukölln, and a moped in the Marzahn-Hellersdorf district. In Neukölln, passers-by prevented greater damage to other cars by putting out the flames.
For the last two weeks, Berlin police have been supported in their investigations by their federal counterparts. Around 500 officers working on the investigation were on duty during the night. The federal operation, which includes helicopter support, is costing the Berlin tax-payer €250,000 per week.
Police estimate that around half of the 540 arson attacks reported this year are down to left-wing extremists, while the rest are thought to be the work of copycats and insurance fraudsters.
The arsonists have proven to be both very difficult to catch or to conclusively link to individual attacks. Police say they often use BBQ fire-lighters to start the blazes, and are well out of sight by the time the car is in flames. The few court cases have mainly ended in acquittals or suspended sentences.
A couple arrested in August has confessed to some attacks, but are not considered to be politically motivated.
The attacks have since become a major issue in Berlin's mayoral election campaign, with the opposition blaming the attacks on Mayor Klaus Wowereit's decision to cut police numbers in the past few years. Wowereit, of the centre-left Social Democratic Party, is currently well ahead in the opinion polls. The election takes place on September 18.