Be/get mixed up in something
Definition 1 of 2
Pro Tip 1/3Negative Connotation
Often implies involvement in something problematic or undesirable. 
He got mixed up in illegal gambling.
Pro Tip 2/3Unintentional Involvement
Can suggest the person didn't intend to be involved. 
I accidentally got mixed up in their dispute.
Pro Tip 3/3Avoiding Responsibility
Used when someone wants to distance themselves from a situation. 
I refuse to be mixed up in your schemes.