Authorities are investigating a case involving an Indiana State Prison inmate burned to death inside his cell.

Thomas Harris died Monday at 4:37 a.m. at Loyola University Hospital in Chicago with burns over 85 percent of his body.

According to ISP officials, staff working the west side of D cellhouse first noticed smoke coming from a fifth-floor cell at 10:30 a.m. Sunday.

Upon arrival, the cell was engulfed in flames with the 60-year-old Harris inside.

Staff members were able to remove Harris, who was transported to nearby St. Anthony Memorial Health Centers in Michigan City, then airlifted to the burn center at Loyola University Hospital, where he died the next morning, prison officials said.

Indiana State Police are conducting the investigation with assistance from the prison's Internal Affairs division.

Harris was serving a 50-year sentence imposed on March 29, 2001, out of Miami County for dealing cocaine.

Because of the Columbus Day holiday on Monday, officials were not available for comment.

Indiana State Police may provide further information as the investigation continues, prison officials said.