2 1/2 y.o. hurts her cousin

[abgbarker]

My 2 1/2 year old daughter is constantly hurting her cousin who is nine months younger than her. It happens both with and without provocation. Sometimes it is when she is angry (cousin stole her toy, etc.), other times she just seems to strike out of nowhere. This has been happening for quite a while now (about 6 months) and I feel like I have tried just about every “parenting method” to get her to stop (reflecting feelings, remove from situation, attention to the “victim,” time-out, re-direction, reacting strongly, reacting gently). Nothing seems to help prevent her from doing it again. I also now have a 2 month old baby, so I can not hover over her every second to prevent her from hurting her cousin. It almost seems like she just has no impulse control. She does not do this with other children, only this one younger cousin. My sister and I are very close, and I am sad to say that we are spending less and less time with them because I simply can not allow my niece to be continually hurt by my daughter. Please help…