California Penal code §594 makes it unlawful for any person to maliciously deface, damage or destroy the personal property of another.
The keyword in a malicious mischief charge is the word malicious. The intent required must be malicious and must be proven to that level by Prosecutors. The act must be carried out with the specific intent to want to cause injury or damage to another, and you intended to commit a wrongful act. If this element is not present, then there is no valid case against you.
Let’s consider two examples. In example A, Dan wants to surprise his girlfriend on her birthday with a new car. He thinks it would be a creative way to tell her by destroying the old car that she drives and parking the new one right next to it. So while she is at work, he goes to her office and pours paint all over her car and writes “Happy Birthday!” all over the old vehicle. Unknown to Dan, is that his girlfriend has driven her father’s car to work, and her co-worker has the exact same car. Dan has actually destroyed the co-workers car.