The government made a list of demands in dozens of categories in a letter to the Sangamon County Sheriff's Office, dated Thursday.
"The Sheriff's Office, along with involved county agencies, has engaged in discussions and pledged full cooperation with the Department of Justice in its review," Sheriff Paula Crouch said Friday.
SEE ALSO | Bodycam video reveals chaotic scene of deputy fatally shooting IL Black woman who called 911
Sonya Massey, a 36-year-old Black woman, was killed in July when deputies responded to a call about a possible prowler at her home in Springfield, Illinois. She was shot three times during a confrontation with an officer.
Sean Grayson, who is white, was fired. He is charged with murder and other crimes and has pleaded not guilty.
The Justice Department wants to know if the sheriff's office has strategies when responding to people in "behavioral health crises," among many other requests.
"The incident raises serious concerns about ... interactions with Black people and people with behavioral health disabilities," the government said.
Andy Van Meter, chairman of the Sangamon County Board, said the Justice Department's review is an important step in strengthening the public's trust in the sheriff's office.
The video in the player above is from a previous report.