An overdose of antihistamine was the cause of death of a 7-month-old baby girl at a babysitter’s house at Aliamanu Military Reservation in Hawaii, according to court documents.

According to an arrest warrant affidavit submitted by Honolulu Police Detective Ryan Kaio, the medical examiner’s July 15 report determined that the baby’s blood tested positive for diphenhydramine, the active ingredient in Benadryl and other similar medications, at a level of 2,400 nanograms per milliliter. That’s nearly twice the 1,400 nanograms per milliliter concentration that is the average reported in infant fatal overdoses, according to the affidavit. A nanogram is one-billionth of a gram.

On July 20, police arrested Navy wife Dixie Denise Villa, on a manslaughter charge, in connection with the death of 7-month-old Abigail Lobisch, who was found dead on Feb. 24. The arrest warrant and supporting document refer to the child as A.L.

In the autopsy report, the doctor noted that children under six years old shouldn’t be given diphenhydramine without consulting a physician, according to Kaio’s affidavit. “Per the over the counter label, when used for self-medication, diphenhydramine should not be used in children [younger than 6), to make a child sleep, or with any other diphenhydramine-containing products (including topical products).”

At the time Villa was a resident of military housing at Aliamanu Military Reservation.

On the morning of Feb. 23, the baby’s mother, Anna Lobisch, dropped off her daughter and two-year-old son with Villa at the Aulani Hotel, where they spent the day at the pool. They returned to Villa’s residence at 6 p.m., according to Villa’s written statement submitted to police. The children, including Villa’s two biological children, seemed “happy and well," according to her statement. They were sunburned from the day, Villa wrote, so she applied lotion.

Villa noted that she made dinner for the children before falling asleep on the couch with the baby, while the other three children played in the playroom. She woke up at about 10 p.m., and took all four children upstairs to the master bedroom to sleep.

The baby was sleeping face down on Villa’s chest, she stated, and the other three children were lying next to her. The baby didn’t wake up during the night, but Villa stated she didn’t think it was unusual, because she thought the baby was tired from being in the sun all day.

According to the affidavit, Villa said she was awakened by her son at about 8:30 a.m. Feb., 24, “at which time she noticed A.L. lying face down on the bed and that her skin appeared ‘splotchy’ and that it was cold to the touch.” Villa admitted to “freaking out a little bit” before taking the baby downstairs and calling emergency services. She performed CPR several times with the operator explaining what to do, before the emergency medical technicians arrived.

Villa told police that the only thing she administered to the baby was lotion to her skin.

The baby’s mother, Anna Lobisch, told police that Abigail had been a “perfectly healthy baby” from birth, aside from getting the flu a couple of times. The baby slept in the bed with her mother, and would wake up about every 30 minutes to an hour, she told police.

Lobisch told investigators she received text messages from Villa during the day that included pictures of Abigail.

Villa made her initial appearance in court in Honolulu Monday; her preliminary hearing is scheduled for Aug. 2, according to Brooks Baehr, a spokesman for the Honolulu prosecuting attorney’s office.

Villa was reportedly operating a daycare in her home without authorization from the base.