A grand jury in Kentucky is scheduled to present its findings into the fatal shooting of Breonna Taylor to a judge on Wednesday.
The emergency worker was killed by police officers who burst into her home at night.
Afterwards, Kentucky Attorney General Daniel Cameron plans to hold a news conference to discuss the grand jury report.
Officials in Louisville, Kentucky’s largest city, are preparing for more protests and possible unrest.
Louisville Mayor Greg Fischer announced a 9pm to 6.30am curfew on Wednesday and urged people to protest peacefully.
Ms Taylor was shot multiple times by officers who entered her home using a no-knock warrant during a drugs investigation on March 13.
The warrant used to search her home was connected to a suspect who did not live there, and no drugs were found inside.
The use of no-knock warrants has since been banned by Louisville’s council.
Mr Cameron’s office has been receiving materials from the Louisville Police Department’s public integrity unit while they try to determine whether state charges will be brought against the three officers involved, he has said.
Officer Brett Hankison was fired from the city’s police department on June 23.
A termination letter sent to him by interim Louisville Police Chief Robert Schroeder said the white officer had violated procedures by showing “extreme indifference to the value of human life” when he “wantonly and blindly” shot 10 rounds of gunfire into Ms Taylor’s apartment in March.
Mr Hankison, Sergeant Jonathan Mattingly, officer Myles Cosgrove and the detective who sought the warrant, Joshua Jaynes, were placed on administrative reassignment after the shooting.
Mr Walker was charged with attempted murder of a police officer but prosecutors later dropped the charge.
He told police he heard knocking but did not know who was coming into the home and fired in self-defence.
On September 15, the city agreed a settlement with Ms Taylor’s mother, Tamika Palmer, which includes 12 million dollars (£9.26 million) and police reforms.
Protesters in Louisville and across the country have demanded justice for Ms Taylor and other black people killed by police in recent months.
The release in late May of a 911 call by Ms Taylor’s boyfriend marked the beginning of days of protests in Louisville, fuelled by her shooting and the violent death of George Floyd while in police custody in Minneapolis on May 25.
Several prominent African American celebrities including Oprah Winfrey and Beyonce Knowles have joined those demanding the officers be charged.