More than a month after Jelani Day's body was found, LaSalle County Coroner Richard Ploch has revealed drowning was the graduate student's cause of death. How Day made his way to the body of water, Ploch notes, remains a mystery.  

"There was no evidence of any (pre-death) injury, such as manual strangulation, an assault or altercation, sharp, blunt or gunshot injury, infection, tumor, natural disease, congenital abnormality or significant drug intoxication," the coroner said, according to CNN. 

As Blavity previously reported, Day went missing on Aug. 24 and was reported missing days later by his family and several teachers who said he hadn't shown up for classes in days. His car was found days later in Peru, Illinois, while his other belongings were found near the Illinois River. His mother, Carmen Bolden Day, launched a national effort to find her son, pleading with the public to share any information about his disappearance. Day's body was discovered in late September.

The grieving mother says she doesn't completely accept the coroner's report, telling NBC Chicago that there are some inconsistencies in the coroner's report and the independent autopsy she ordered. Previously, there were reports that several of Day's organs were missing, but a coroner said that was only because they had been removed in the first autopsy. Ploch said the organs had actually been badly decomposed from the water. 

"There were contradicting facts from the first preliminary autopsy compared to the second independent autopsy, but this is not a case of organ harvesting, however, my son did not put himself in a river," she said in a statement.

Bolden Day continued to emphasize her stance on the findings at a general meeting of Illinois State's Black Student Union, where she was joined by the Rev. Jesse Jackson Jr.

"That is a narrative that my son did something to himself. He did not," she said.  "Somebody did this to him, and they are going to be held responsible for doing what they did to my son."

Jackson echoed her sentiments, telling the crowd that he refused to believe the coroner's conclusion.

"That's a suicide line. We don't believe it," Jackson said. "The Department of Justice and the attorney general needs to be a part of this."

"Who killed him must pay a price," Jackson continued. "That's why we march tomorrow."

The reverend has put pressure on the FBI and the U.S. Department of Justice to launch a complete investigation "because it smells like another Emmett Till case all over again."

Bolden Day said in a statement, "My son was murdered, and my goal and purpose are to find out what happened and hold those responsible accountable!"

"Jelani, if you would have met him, anybody under the sound of my voice that would have met him, you would have loved Jelani," Bolden Day told CNN. "Jelani was very driven, outspoken, but also he was the most caring, compassionate, protective son, grandson, brother, friend, cousin, nephew that you would have wanted to have. Jelani was one of a kind."

carmen-bolden-daycause of deathJelani-DayReverend Jesse Jackson