Jelani Day's death is said to have been caused by drowning, according to the LaSalle County Coroner's Office. The 25-year-old college student went missing in August, while studying to be a doctor at Illinois State University.
Day was last seen on Aug. 24 at the university's campus in Bloomington, Illinois. His parents reported him missing on Aug. 25 and his car was found two days later in Peru, Illinois.
Day was found dead, floating in the Illinois River on Sept. 4. His body was not identified until weeks later by the LaSalle County Coroner, on Sept. 23.
"Unfortunately, there is no specific positive test at autopsy for drowning," coroner Richard Ploch's statement read Tuesday. "Drowning is considered a diagnosis of exclusion with supporting investigation circumstances when a person is found deceased in a body of water."
The coroner did not find any evidence of intoxication or injury in the forensic autopsy -- no signs of an assault, altercation, strangulation or more -- and it remains unknown how Day ended up in the Illinois River.
Day's family still suspects foul play in the young man's death, and said that his personal belongings were found scattered away from where his body was found.
"Jelani did not just disappear into thin air. Somebody knows something, somebody seen something and I need somebody to say something," Day's mother, Carmen Bolden Day, told "Good Morning America" on Sept. 29.
The case is still being investigated by local police jurisdictions in the area, along with the FBI.