Sounds familiar -- my oldest sister was my tormenter. She's 7 years older than me, and many times was left in care of us when my parents went out.
She used to beat me up -- she never touched the other 2, but just me. For some reason she thought it was funny to beat me up and torment me, emotionally & mentally. She'd embarrass me any time she got the chance.
She'd do all kinds of evil things, and then tell my folks that *I* did them and they believed HER -- and of course I'd get punished because she was older and they believed HER. They never listened to a thing I said.

This went on until she left home at 19 -- and i was 12. isn't it funny that none of those things never happened again and they couldn't see the forest thru the trees???
She came home for my mom's funeral -- my sister was 59yrs old. She started tormenting me ALL OVER again, right in front of my daughter. Wouldn't you have thought she would have grown up?