Berlin: Police in Berlin on Friday admitted problems tracking arsonists, who have ignited a political row ahead of regional elections as a dozen more cars were torched for the fourth night in a row.
German Chancellor Angela Merkel, expressed deep shock at the attacks, which police and city mayor Klaus Wowereit insist are purely the work of vandals.
The total number of cars set ablaze in the capital this year stands at 159, 75 of them this month alone.
"We don`t rightly know the reason for it," police spokesman Guido Busch told a news agency.
"But, we believe it is mostly the work of a single person, or a single group of people, and that it is vandalism with no political motive," he added.
He did not rule out however, that the current spike in attacks could be due to mischief-making copy-cat behaviour, or attempts to collect on insurance money.
Wowereit called on Berliners "to help arrest the culprits by reporting suspicious activity to the police," who have offered a 5,000-euro (USD 7,200) reward for information leading to an arrest.
"This is a case of pure vandalism and criminality," he told reporters.
Berlin police chief, Margarete Koppers, tried to explain, why no one has yet been arrested.
"It takes at least 15 minutes between the moment, when an arsonist places his barbecue set against the wheel of a car and the moment it goes up in flames, largely enough time to get away," she told a newspaper.