The results of an autopsy conducted on an 8-year-old girl who died Thursday after experiencing a medical emergency on a flight from Joplin, Missouri, to Chicago were ruled inconclusive, reported WEEK-TV, the NBC affiliate in Peoria.

Sydney Weston was going on vacation with her family when she suddenly became ill and then unresponsive early Thursday morning. Her family informed flight personnel, who started rendering aid.

The plane made an emergency landing in Peoria, where Sydney was found not to have a pulse. Police and fire personnel attempted life-saving measures and transported her to the hospital.

Sydney was later pronounced dead, authorities said.

The Peoria County Coroner said an autopsy didn’t find any evidence of foul play or signs of abuse. More information could be revealed once the coroner receives results from toxicology and blood tests, among others.

Results should be released within four to six weeks.