My sister can not support herself and her two children living in California on there own. All of her family and her ex's family live in Minnesota where they always planned on moving back to. Now that she left him he does not want her to move back to Minnesota. Could she still leave with the kids without his permission if they have no custody agreement yet and niether one has filed any papers except for child support?

She should seek legal counsel that practices law in California to get proper custody papers because I believe he could file abandonement and kidnapping charges against her possibly. I am not an attorney but that would be my guess. Have her get the proper papers filed with the court first though, then he has no legal grounds to make her turn around and bring them back.