A stranger blew up a speed camera in Böblingen near Stuttgart.
The technology of the radar column was badly damaged, as a police spokesman said on Sunday.
The perpetrator fled after the explosion on Sunday morning.
The police then looked for him with several patrol cars and a helicopter.
The manhunt was unsuccessful.
According to the information, the damage is estimated at around 10,000 euros.
The investigators are now looking for witnesses to the crime.