The Lake County, Indiana Coroner's Office said 31-year-old Cordero M. Hill was pronounced dead at the Powers Health East Chicago Emergency Room on Sunday.
Hill was in custody at the Whiting Police Department Jail at the time of a medical emergency, police said.
How Hill died was not immediately clear. The coroner said his cause and manner of death are pending on Tuesday.
The Whiting police said the incident is under review, and the department requested that the Lake County Sheriff's Department lead an independent investigation into Hill's death.
Further information was not immediately available.