Granted, you can now kill a single person of your choice without being caught. The police searches for weeks and months on end, with every clue leading towards you, but through magical reasons, each time the conclusion points to you, their thought process is reset, and the investigation goes on forever, despite everyone's protests. Eventually the local police office run out of funds, and people protest more. Meanwhile, the police force keeps going in their endless looop of never finding you. Eventually people riot, and the crime rates explode.
I wish for the next wish not to come true.