Frazer Harrison, WireImage
According to both PEOPLE Magazine and HollywoodLife, Leslie had been battling depression for quite some time. In a statement to the Chautauqua County sheriff, Ginger Carter, Leslie's half sister, revealed that the deceased had "a long history of mental illness" and seemed despondent the morning that she passed.
Leslie, who was found unresponsive in the upstate New York city after falling down in the shower, had medication to treat schizophrenia, bipolar disorder, and anxiety, as well as a muscle relaxant near her body. "She was battling a major addiction and yes, it was a surprise when she suddenly died," a source tells HollywoodLife. "But before anyone even said what caused it, everyone thought the same thing. She battled a prescription drug addiction for a while. Some think that she was even battling postpartum depression, too."
Another source tells the gossip web page that the pressure to make it in the music industry not only drove Leslie to depression, but also fractured the once-close Carter family. "Everyone in that family is trying to make it in Hollywood and it caused jealousy and pitted some of them against each other," a source says. "When Leslie got married, several members of her family didn't even attend. Close friends definitely find it strange that Nick isn't taking time off to go be with his family and he's instead performing in NYC - even though he did dedicate his tour to her. Many think the way the family is handling it is very bizarre."
Both Aaron Carter and Nick Carter have released statements thanking fans for their support. We'll keep you updated as this story develops.