I’ll venture a guess and say she was arrested for tampering with evidence or the crime scene.
looks like the “victim” and the would be robber and accomplice all knew each other. Clearly, it’s just a spat between drug dealers.
Had this been a regular woman defending herself from a creep, I’d say “that’s my kind of girl!” but maybe she isn’t in this case...
She should have shot the accomplice as well. That’s the lesson.