A criminal investigation was started after a collision with a bus in Kungsbacka in December.
It is established that Heikkinen Breitholtz had drug-classified medicine in her body, which was also slightly above the dose prescribed by a doctor.
But according to the former member of parliament, she took the preparation immediately after the collision - which she believes was caused by the fact that at the time she had run out due to pain.
- I can not disprove it and must therefore write off the case, says prosecutor Anders Jakobsson.
SVT Nyheter Halland has searched for Sara Heikkinen Breitholtz (S) without success.