IIRC, she had a problem with Xanax at the time of the Csaba Marton imbroglio.

I have also known heroin junkies whose sole use for methadone was to boost the high from the junk. Really dangerous.

Of course, none of this answers the question: What were they doing in King City?

Or, for that matter: What did the cops have, know or sense, that caused them to book Inkyo on suspicion on Murder?

We may get more answers when his own autopsy is complete.