02/02/2012 at 02:00 PM EST
Leslie Carter, the 25-year-old sister of Nick and Aaron Carter, suffered an apparent overdose and had been taking medication for depression, according to a police report released Thursday.
Leslie, who was an aspiring singer, died on Tuesday
in upstate New York. An official cause of death is pending toxicology tests.
Her stepmother, Ginger Carter, told authorities that Leslie had "a long history of mental illness" and seemed depressed the morning before she died, according to an incident report from the Chautauqua County sheriff.
Leslie was staying at her father's house with her 10-month-old baby. She had coffee that morning on the porch with her stepmother and complained that she was "not feeling great," the report says.
She then went to the bathroom and stayed in there so long that Ginger became concerned. Ginger spoke to Leslie through the door and found out that Leslie had fallen in the shower.
Ginger then helped Leslie lie down in bed and Leslie appeared to fall asleep. At one point, Ginger brought Leslie's baby into the bedroom "in the hopes that [Leslie] would wake up and play with the baby."
"Ginger stated that [Leslie] did not wake up but seemed to be okay and just sleeping," says the report. "Ginger states that she looked at [Leslie] and she had all the color to her skin and was breathing. Ginger took the baby out of the room and closed the door."
Leslie's father came home around 4:16 p.m. and Leslie "was found in the bedroom not breathing or responding," says the report. Robert attempted CPR and then 911 was called. Leslie was pronounced dead at the hospital.
Authorities had found near Leslie medication to treat schizophrenia, bipolar disorder, and anxiety, as well as a muscle relaxant.
Authorities later interviewed Ginger, who "appeared to be under the influence of an unknown drug" and had "slurred speech, pin-point pupils, glassy eyes and kept falling asleep."
Ginger said she had taken as many as six pills, including possibly Xanax, and as her police interview continued the officer became concerned that Ginger was at risk of an overdose.
"Ginger stated that she is only supposed to take four [pills] but Robert gave her an extra one because of Leslie passing away," says the report, which does not say whether Ginger received medical attention.
Reporting by MARISA LAUDADIO