Police have charged four people in the death of Michael Williams, a Black man whose body was found burning in a ditch in Kellogg, Iowa, The Daily Beast reports.

Williams was strangled on Sept. 12 and according to Iowa authorities, his death was “not a random act of violence.” He reportedly knew at least one of the suspects for years. According to the Iowa Division of Criminal Investigation, one of the suspects, Steven Vogel, 31, was a “known acquaintance” of Williams and has been charged with first-degree murder and abuse of a corpse. The remaining suspects, Julia Cox, 55, Roy Garner, 57, and Cody Johnson, 29, face charges for abuse of a corpse, destruction of evidence, and accessory after the fact. All four have been arrested in the death of the 44-year-old Williams, per CNN.

After Williams was killed on Sept. 12, he was taken to rural Kellogg on Sept. 16, where he was discovered. Iowa DCI Special Agent Adam DeCamp said during a press conference on Tuesday that “no evidence has been found to show the acts against Michael Williams were motivated by his race.”

Grinnell Police Chief Dennis Reilly reiterated the fact that Williams and Vogel knew each other for “years.”

“Our mission from the very beginning and that will continue is to bring justice for Mike and Justice for his family,” Reilly said. “I just want to be clear to say: This was not a random act of violence. Those responsible for this heinous act knew each other.”

Police officers discovered Williams’ body just after 5:30 p.m. on Sept. 16, after someone had reported a roadside ditch fire. The medical examiner’s office ruled Williams’ death to be a homicide, adding that the evidence was “consistent with strangulation,” DeCamp said.

Williams was a grandfather and had five children with ex-wife Janalee Boldt. “He was a family person,” she told CNN affiliate KCCI. “His kids were always important.”

“My daughter will not let me outside in the dark by myself because she's afraid of losing another parent,” Boldt added. The family has made “Justice for Michael” shirts using a logo that her son designed, which incorporates Williams’ favorite color, purple.