Four people were charged on Tuesday in connection with the killing of a Black man in rural Iowa whose body was found burning in a ditch last week, The Des Moines Register reported.

Michael Ronnell Williams was found dead in a ditch in Grinnell on September 16.

Steven Vogel, 31, who authorities said was an acquaintance of Williams, was charged with first-degree murder and abuse of a corpse, the Iowa Department of Public Safety said on Tuesday.

Julia Cox, 55, Roy Lee Garner, 57, and Cody Johnson, 29, were charged with abuse of a corpse and accessory after the fact. Cox and Garner face an additional charge of destruction of evidence.

Though all four suspects are white and Williams was Black, the police said at a press conference on Tuesday that there was no evidence to suggest that Williams' killing was motivated by race, according to The Register.

Authorities did not say what prompted Williams' killing.

Vogel's arrest affidavit said a witness told the police that Vogel had strangled Williams four days before his body was found.

The affidavit said another witness told investigators they'd heard that Vogel kept Williams' body for several days in the basement of the home where he lives with Cox and Garner.

The affidavit said Johnson told authorities that Vogel had tried to get his help in moving the body on September 13 but that they were unable to do so.

Cox and Garner told investigators that on September 16 they helped Vogel dispose of a long, wrapped-up object — Garner said it was wrapped in a rug, while Cox said it was wrapped in a blanket, the affidavit said.

They said that afterward they dropped Vogel at his sister's house, then went to a rural area where they disposed of the remaining items in Garner's vehicle, including bleach bottles and rubber gloves, the affidavit said.

The police's Tuesday press conference was held with the NAACP's Iowa-Nebraska chapter, whose president, Betty Andrews, said she had seen the evidence and agreed that the killing didn't appear to be motivated by race, according to The Register.

"Given that the current climate where racial justice is on the front burner for so many ... we understand the fear this kind of incident evokes," Andrews said.