Leslie Carter was battling addiction to prescription drugs in the days before her death, and family members believe she died as a result of an overdose.
According to TMZ, the 25-year-old sister of Nick and Aaron Carter recently moved from Canada to Upstate New York to live with family members.
Leslie Carter had been attempted to kick her addiction, they say.
The family had attempted to rid the home of any prescription medication, including Xanax, and were hopeful that Leslie was on the road to recovery.
Close sources say that family members believed Leslie would be OK to stay alone in the home for roughly an hour yesterday while they ran errands.
Her one-year-old daughter was not home at the time of her death.