A 3-year-old child died on Thursday aboard a bus of asylum seekers that was headed to Chicago, the Illinois Department of Public Health (IDPH) confirmed in a statement Friday.

An investigation is underway to determine the circumstances behind the death.

“IDPH is working with local health officials, state police, and federal authorities to the fullest extent possible to get answers in this tragic situation,” read the statement released by the department. The spokesperson did not respond directly to questions on the cause of death or any related details.

Since last year, Texas Gov. Greg Abbott ® has bussed some 12,000 migrants to Chicago, as well California and other liberal enclaves.