What happens if politicians are wrong?

During the recent days, I was going thru the media and one story really raised the above mentioned question to me.

Andreas Scheuer, the former state secretary of traffic in Germany, is challenged to be made personal responsible for the money he wasted to introduce a highway toll in Germany. It was a project that took about 2-3 years, was backed up by the former coalition and did fail quite dramatically, wasting over 430 Million Euro of tax money. Money, that had to be paid to the selected future suppliers for this highway toll, as they simply did what had been asked from them. But the entire project was badly managed and assessed. And on top, several responsible people lied publicly about the status, the possibilities and the consequences of this project.
Well, this would not be the first time, that any government is setting up projects, that aren’t working. And not the first time, that tax money would be thrown out of the window. And not the first time at this level.
The interesting question is really, if a responsible state secretary should be made personal accountable for such a wrong-doing. Scheuer in this case, was holding on to the project until the very last moment and he kept hiding a lot of information or he was even lying in public. For all of that, it looks like there are proofs in place.
Nevertheless, the general question is much more, if a state secretary should have a personal accountability for these kind of things. I read today, that if a state secretary would throw a rock into a window s/he would be accountable for the damage and would need to pay the damage. The same applies for me. If I would take money from investors for a project and then I would lie about this progress to the investors, they would accuse me personally for the damage. If the project would fail because there are topics happening outside of my control, I would not be accused.
It all comes down to the evidence that somebody did something intentionally wrong. And my conclusion is, that the same should apply for politicians. If there is an intentional wrong-doing and this can be proven, the should have the same consequences than private people being in a similar position. A politician can’t have a carte Blanche for all the actions s/he is taking.
As a consequence I do believe, that politicians should be regulated and monitored, even after their legislation period. And they should be held accountable for their doings – positive as well as negative.