Aaron made his comments on Twitter on Thursday soon after revealing his mental health issues and while feuding with the Backstreet Boys singer, who has filed a restraining order against him. Leslie, one of their four sisters, died at age 25 in 2012 after suffering a prescription drug overdose.
"My sister Leslie suffered from bipolar and took lithium to treat it," Aaron tweeted. "She never liked the way it made her feel and when she was off of it she did things that she never meant to do I truly believe that. I was 10 years old...."
"My sister raped me from the age of 10 to 13 years old when she wasn't on her medications," he continued.
Aaron also claimed to be abused by backup dancers early in his career.
"And my brother abused me my whole life," the singer added.
Aaron also tweeted, "Now it's nicks turn to tell the tell the truth of what he did to one of the girls in my family. Since my truth is all out there and I hope all survivors of assault or rape find peace and justice."