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Ky. official: Gynnya McMillen appears to have died "while sleeping"

Gynnya McMillen

LaChe Simms via Facebook

Last Updated Jan 21, 2016 10:13 PM EST

NEW YORK -- Officials say a 16-year-old Kentucky girl who was found dead in a juvenile detention center cell on Jan. 11, "appears to have passed away while sleeping."

Gynnya McMillen died less than 24 hours after arriving at the Lincoln Village Juvenile Detention Center in Elizabethtown, Ky. In the 10 days since her death, few details had been released about the circumstances of her confinement, even as friends and family launched a social media campaign seeking answers.

But in a statement released to media on Thursday, the Kentucky Justice and Public Safety Cabinet said its Secretary, John Tilley, has asked that the investigation into McMillen's death be expedited.

"The youth appears to have passed away while sleeping and the preliminary autopsy report shows no cause or manner of death," according to the statement. Hardin County Coroner William Lee, Jr. said in an interview with 48 Hours' Crimesider Monday that the preliminary autopsy on Jan. 12, showed no outward signs, such as "visual bruising," which could conclusively signal a cause of death. Lee also said it was unlikely she had a heart condition.

The full autopsy, previously expected to take weeks, will be expedited as well, the department said in the statement, in which it said its "deepest condolences are extended to the family." State officials are awaiting toxicology tests, electrolyte analysis and a histology report, according to the statement.

It is not clear why McMillen was alone in the cell where detention center staffers say she spent her last night. Officials have not said how often she was checked on during the night and morning she was at the Lincoln Village Juvenile Detention Center.

However, the Justice and Public Safety Cabinet's interim spokesperson Lisa Lamb confirmed today that "standard operating procedure" at the Lincoln Village Juvenile Detention Center requires room checks every 15 minutes.

"Policy further provides that residents will not be left in a room unattended when staff is absent unless that room has a camera in it," Lamb said.

Lamb confirmed Thursday that there was a camera in McMillen's room, and a copy of the video footage was provided to investigators.

McMillen, of Louisville, was first detained Jan. 10 after what police describe as a "domestic incident" at her mother's home in Shelbyville, Ky. Police say they called a court-designated worker -- a Kentucky official who makes legal decisions related to juveniles. That worker contacted a judge and requested that McMillen be detained, according to police. McMillen was charged with misdemeanor assault in the incident.

By 10 a.m. on Jan. 11, McMillen, described in interviews with 48 Hours' Crimesider as a "quiet, beautiful person," had died.

Officials had previously indicated that the investigation into McMillen's death was being investigated by the Kentucky State Police. In the statement, the Justice and Public Safety Cabinet said its Internal Investigations Branch is now also investigating.