Thanks for this.
The castle fire wasn't actually the only one for Risto, half a year prior to that his rented property in Tallinn Old Town caught fire aswell. And he had some strange parties going on all the time, he even had his own imaginary money which could be used there. They do suspect that the castle fire was self ignited.
Good thing Rpietila was out of the country at the time. I am sure the insurance company will fight it hard...