Lying...

What do you do when your kid lies to you? The last few weeks Eli has lied to us a couple of times. At first I ignored it to see if he would stop. It did not. I just recently cut Sarina's hair and it was cute, not the best cut I have done on someone but cute. Next thing I know,I see more hair on the bathroom floor. I proceeded to ask who cut her hair and Eli says "mom Sarina did it". humm, I don't think so. I wanted to believe him because I caught her with scissors right after I cut her hair and she was cutting it herself. They were both in the bathroom though. SO I know sarina already got into trouble. I asked Eli again "are you lying to me". "ok mom, I did it". UG I was so mad. He gave her some more bangs than I would have. I told him he doesn't get to play xbox until sat. Which is a week of being grounded. I thought it was fair. We have a schedule of when he can play now because he plays a lot. So taking it away completely would torture him. He has asked every day this week to play. Of course I made him take a nap yesterday for lying and for not staying in time out when I told him to stay for lying to me. SO it was an instant nap for him. He got out of the room one time, then I put him back and he slept 2 hours. David told his co workers that our kid got grounded for a week from the xbox and they thought it was to long for a almost 5 yr old. I don't do lying at all. I can almost always tell now when they lie to me. What do you do when your child lies?