Robert Loeffel, press spokesman in the South region, says that the police found plastic after burning cables at the site.
It is suspected that it was thieves who stole copper cable that caused the fire.
- When you have stolen copper cable, you want to get rid of the plastic and then you burn it away, says Robert Loeffel.
They have also found traces of a ditch-harvested car nearby, but it is not yet known if it has anything to do with the police's suspicions.
So far there is no suspect.
- It is probably difficult to move forward with this, says Robert Loeffel.