BLOOMINGTON, Ill. (AP) — The FBI is offering up to a $10,000 reward for information on the final hours of an Illinois State University graduate student who disappeared in August and was later found dead in a river.

Jelani Day, a 25-year-old Illinois State University graduate student and Danville native, was reported missing on Aug. 25, a day after he was last seen in Bloomington, Illinois. His body was found in the Illinois River near Peru, 60 miles north of the ISU campus, on Sept. 4.

Authorities later determined he died by drowning, but have said his death remains under investigation.

Day’s mother, Carmen Bolden Day, said law enforcement officials have all but told her they believe her son died by suicide, which she dismissed out of hand. She said her son was not depressed or overburdened, had no school-related financial troubles and was studying speech pathology at Illinois State with aspirations of becoming a doctor.

She has hired civil rights attorney Ben Crump to investigate her son’s death.

The FBI said it is offering the reward of up to $10,000 for “substantial information regarding Day’s final hours leading to the identification of new witnesses or evidence.”

The agency added a “seeking information” post to its FBI’s Most Wanted website late Friday that includes a description of Day’s disappearance and three photos of Day, The Pantagraph reported.

Anyone with information is asked to call 1-800-CALL-FBI (1-800-225-5324) or go to tips.fbi.gov. Tips can be submitted anonymously.