N.K.
She may be expressing anger about something, or copying something she saw on TV. She may also be wanting attention and knows that by vandalizing objects, she will get some sort of attention. I work full-time, and my daughter never did any of these things so no, the fact her mother works is not the reason. It could be one of MANY reasons she is angry about being ignored, bullied, or what have you, but it is not THE main reason she is resorting to this. Maybe she is resenting the attention her little brother is getting? The only way to find out is to try to ask her, or going to therapy.