Interstate Issues: How Can I Prove That She is Lying

My question involves a child custody case from the State of: CA. The mother of my child say's she live's in another state but she doesn't. I know she live's here still. what do i have to do to prove she is lying, take pictures or a video. She live's with her boyfriend so nothing is in her name.

Interstate Issues: How Can I Prove That She is Lying