Autopsy results of migrant child who died traveling on Texas bus to Chicago 'inconclusive'

Authorities are trying to determine what caused the death of a 3-year-old girl who was traveling on a Texas-funded bus transporting asylum seekers to Chicago on Thursday.

Preliminary autopsy results from Friday proved inconclusive, Marion County Coroner Troy Cannon said.

"The Marion Co. Coroner's Office is currently investigating the death of a minor who died en route to another location. Preliminary autopsy results from early Friday were inconclusive but microscopic studies of tissue samples may provide a definitive cause of death. More information may become available in the coming days but no further information will be released at this time," Cannon said in a statement.

Cannon told ABC News that the child had diarrhea, vomiting and a low-grade fever before their death.

The Illinois Department of Public Health confirmed the child's death last Thursday.

"IDPH is working with local health officials, state police, and federal authorities to the fullest extent possible to get answers in this tragic situation," an IDPH spokesperson said at the time.

Sources confirmed to ABC News the bus departed from Brownsville, Texas.

In a statement released Friday, the Texas Division of Emergency Management said "bilingual security personnel translated for the parents and the paramedics" when first responders arrived. The child was later taken to a hospital and later pronounced deceased.

According to TDEM's statement, once the child showed signs of health concerns, the bus pulled over in southern Illinois, 911 was called, and an ambulance arrived. According to the statement, the parents spoke with paramedics through a "bilingual security personnel."

The child was transported to a local hospital to receive additional medical attention, according to TDEM's statement, where the 3-year-old was later pronounced dead.

Before the bus departed from Brownsville, "each bus passenger underwent a temperature check and was asked if they had medical conditions that may require medical assistance," TDEM said in its statement.

According to the statement, after no passengers presented medical concerns or a fever, the bus departed, and "each bus is stocked with food and water, which are distributed on board."

TDEM has not responded to multiple requests for comment and did not disclose whether the security personnel onboard have medical training.