CARBONDALE, Ill. -- Two men remain hospitalized after a plane crash early Tuesday evening near DeSoto, Ill.

Both men were natives of Bombay, India.

The pilot, Iyer Ranganathan, was taken to St. Francis Medical Center. He was listed in critical condition at the hospital's surgical intensive care unit.

A passenger, Rai Kulbir Singh, was taken to Memorial Hospital of Carbondale. A hospital spokesman said he was listed in satisfactory condition.

The Jackson County Sheriff's Department said the men were associated with Airgo Inc. of Centralia, Ill.

Authorities are still unsure what caused the crash, which occurred near DeSoto at 6:19 p.m. Tuesday.

An investigation is being conducted by the sheriff's department and the Federal Aviation Administration.