mixed up in (something)
Involved or embroiled in some situation or circumstance, especially that which is problematic, unpleasant, dangerous, etc. I don't want Sarah getting mixed up in any of your boss's illegal dealings, you hear me? He's been mixed up in some pretty shady activity, from the sounds of things.
*mixed up in something
involved in something, especially something wrong or illegal. (*Typically: be ~; get ~.) The youth has had problems ever since he got mixed up in a group of boys that stole a car.