OTTAWA, Ill. (CBS) — The LaSalle County Coroner’s office announced Monday that Illinois State University student Jelani Day’s death was a drowning.

Day’s body was discovered in the Illinois River in September, more than a week after he went missing.

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“Unfortunately, there is no specific positive test at autopsy for drowning. Drowning is considered a diagnosis of exclusion with supporting investigation circumstances where a person is found deceased in a body of water,” the Coroner’s office said.

The Coroner’s office said the examination of Day’s body was “suboptimal” given the decomposition his body had undergone, but there was no evidence of any kind of injury he had suffered before his death such as an assault, strangulation, or gunshot wound – and there was also no evidence of significant drug intoxication.

It was not clear how Day ended up in the river.

The ruling amounts to some level of closure for Day’s family, who have been very vocal about his disappearance – and were likely still left with many questions.

As CBS 2’s Meredith Barack reported, Day was last seen at a cannabis dispensary near the ISU campus in Bloomington on Aug. 24.

The 25-year-old grad student’s car was found two days later in a wooded area near the Illinois Valley YMCA in Peru – which is in LaSalle County, 60 miles north of Bloomington.

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When his body was finally identified on Sept. 23, police called it all “very suspicious.”

Last week, he was laid to rest.

Day’s mother, Carmen Bolden Day, said after Day’s body was found that officials didn’t do enough to help find her son.

“To them, Jelani didn’t mean anything. There’s no effort, there’s no push, there’s no nothing that was being done about my son,” she told CNN. “I did all that legwork. Me and my kids, me and everybody that never knew Jelani, my family, friends, strangers, did all the legwork. My son didn’t get any type of help, and I’m pissed, because he didn’t deserve this.”

Day’s mother pointed out the racial disparity in her son’s case, noting Jelani’s disappearance received nowhere near the attention of Gabby Petito, a White woman who disappeared while touring national parks with her fiancé, and was later found dead near Grand Teton National Park in Wyoming.

Bloomington Police said Jelani’s case did receive significant attention, and generated tips that helped investigators locate his body.

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The Rainbow PUSH coalition and the Rev. Jesse Jackson are hosting a Justice for Jelani Day march on Tuesday in Peru. It starts at noon

Meredith Barack