Hello I am new here 
, just wondered if anyone has had any experience or thoughts about a new behaviour my 6.5yr old dd is showing, this is the second time she has done this:we are getting ready to go to school, have asked kids to wait in backyard, whilst I run to grab last couple of bits. I hear my 8.5yr dd old asking 6.5yr old dd why she is smiling at her, next thing 6.5yr old dd comes in, with a red mark on her face and states that her sister has smacked her in the face.....I come out and 8.5yr dd is calm, I say what 6.5yr old dd has stated, 8.5yr dd said she didn't so I run a re-enactment, to find out what has gone on....I realise that 6.5yr old dd didn't cry out or shout or say anything at the time, which you would expect if someone hit you in the face....(I was right by the back door) 
...also that 8.5yr dd is not flustered or angry, so I'm meant to believe that 8.5yr dd just smacked 6.5yr old dd for absolutely no reason, something's not right...I say 'no, I don't buy it!' , also she had accused her big sister of something similar a few days ago which had transpired to have been a fib! We walked to school, I am annoyed with my 6.5yr old dd 
. I decide to plump for my gut instinct and say, 'This behaviour is unacceptable, think of how kind your big sister is to you' to which with a sad tear in her eye she replies 'sorry'. So I think some more and say, I'm going to talk to Daddy abouth this later, for now I want you to think about why you have done this and no treats/sweets etc for five days....to which she responds quite chipperly...'okay so that means I can have some on Saturday...' Sorry this is very long winded!! The thing is I believe she lied and also I think she smacked herself in the face to get a red mark!! Generally they get on really well, a bit of squabbling, but they don't hit each other, and 8.5yr dd is extremely kind. I don't understand why 6.5yr old dd would do this? 