Teen skipping class, lying - RAD

What should the consequence be for skipping class and lying about it? She is a chronic liar. We want the punishment to fit the crime and we usually stay out of the school issues and that approach has worked out pretty good for us. We let the school deal with her and her grades are okay. We don't hound her about her homework, just let her figure it out and she does. But now that she's skipping class we need to intervene because I think the school is pretty lax about the consequence for that, besides her grades will start to suffer because she isn't in class, we don't know where she is or what she is doing that's another concern. So what's the best approach when dealing with a teen with attachment disorder and skipping class? Thanks!