Jelani Day's family suspects foul play in son's death, urges public for answers: 'Somebody knows something'

The family of Jelani Day, an Illinois grad student and aspiring doctor whose body was found floating in the Illinois River, is desperately searching for answers.

Day's body was found on Sept. 4 and was identified by the LaSalle County Coroner on Sept. 23 through forensic dental identification and DNA testing.

"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 Wednesday.

"I'm very upset because I can't even look at my son's body. His body has deteriorated to the point where I can't say a proper goodbye to him," she said.

The 25 year-old was living in Bloomington, Illinois, and studying at Illinois State University and was reported missing by his family on Aug. 25 -- two days after they had last spoken with him, according to a joint press release from police and the LaSalle County Coroner's Office.

He was last seen at the university campus on Aug. 24 and his car was found two days later in Peru, Illinois.

Family attorney Hallie Bezner told "GMA" that Day has never been to Peru before and his family suspects foul play.

"The wallet was found in a different area. The lanyard, which it had a school ID on it was not found with the wallet, it was found in a different area -- the area with some clothes that were found last week," Bezner said.

Police in Peru are working to identify a man captured on security cameras knocking on the front door of a home that is close to the location where Day's body was found. The video was captured a day after Day was last seen and police are urging the public to help identify the man.

The home is in an area that is predominantly white and the owner of the property said that he did not know the male captured on the home security video but after seeing images of Day on the news, sent the video to the police, thinking it could be Day.

Bolden Day said that the Black male seen in the footage is not her son, but wondered whether the man in the video could be connected to her son's death and said she wished the video had been shared with the public sooner.

Day's cause of death has not been determined and authorities have not yet named any suspects in Day's death.

Bolden Day said it was frustrating to see cases like 22-year-old Gabby Petito, a travel blogger whose body was found in Wyoming, get media immediate attention, while her son's death did not get widespread coverage until his body was identified weeks later.

"I see that Gabby is missing and I see [her] getting the help. I wasn't getting that attention," she said.

Since his body was identified, Day's death has garnered the attention of celebrities like Viola Davis and Lizzo, who have helped share his story and urged the public to help in getting answers surrounding his death.

"Jelani was ambitious. He was driven. He was focused. He was energetic. He was full of life. Jelani was a person that you couldn't help but love," Bolden Day said.

ABC News' Vera Drymon and Jessy Mendoza contributed to this report.