Is it known whether she had anything in her system before they picked her up? There may have been circumstances that weren't admissable that aren't publicly known. She may already have been under the influence (of her own accord or otherwise). Or she could have been on medication that would have caused something else to act more potently than it might have done otherwise.
Good points. My understanding is that any testing for drugs may have been too late to be accurate. Others here have said that the drug used is known, where it was acquired from, etc. If that is true, it will hopefully come out.
What happened was terrible. The least we can do is try to understand what could have been done to prevent it.
It is obvious that changing the attitudes of people who poo-pooh this kind of stuff is critical. And that includes the whole “safe sex” mentality, that people are animals and can’t help but behave like animals.