my husband and i went to do some shopping. i have two daughters. their names are libby and tanya. libby is twelve and tanya is ten. since we are out, libby is in charge. our daughters are pretty close and tanya is usually an obedient little sister. on that day, tanya was outside playing with a little boy named bobby, who is six. they got into a fight. tanya pressed bobby`s head down the toilet. that is not normal behaviour for my younger daughter. bobby has an older sister called rachael, who is the same age as libby. as soon as that incident happened, rachael told libby about it because they are good friends. then libby helped rachael press tanya`s head down the toilet. that is not normal behaviour for libby either. she is usually so protective of her little sister. what should we do about it?