Mr. Walker has said that he and Ms. Taylor did not know who was at her door. Only one neighbor, out of nearly a dozen interviewed by The New York Times, reported hearing the officers shout “police” before entering.
The warrant for Ms. Taylor’s apartment was one of five issued in a case involving her ex-boyfriend Jamarcus Glover, who is accused of running a drug trafficking syndicate. At the other addresses that were searched, officers found a table covered in drugs packaged for sale, including a plastic sachet containing cocaine and fentanyl, police logs and a laboratory report show.
The surveillance leading police officers to Ms. Taylor’s home included a GPS tracker showing repeated trips by Mr. Glover to her home; photographs of him emerging from her apartment with a package in his hands; footage showing her in a car with Mr. Glover arriving at one of the trap houses he operated; and his use of her address on bank records and other documents. The F.B.I. has opened an investigation into whether the inclusion of her name and address on the warrant violated her civil rights, as her family’s lawyers have claimed.
The announcement on Wednesday revealed several new details in the case. Investigators at an F.B.I. laboratory reviewed the ballistics evidence and concluded that the shot that killed Ms. Taylor was fired by Detective Cosgrove. A total of 32 shots were fired by the police: 16 by Detective Cosgrove, 10 by Mr. Hankison and six by Sergeant Mattingly. The attorney general said none of Mr. Hankison’s rounds struck Ms. Taylor.
Mr. Cameron, who ran on a law-and-order platform, said the investigation and the grand jury determined that the police had properly knocked and announced their presence before bursting into Ms. Taylor’s apartment — a point disputed by Mr. Walker and by a number of neighbors who have said in interviews with reporters that they heard no announcement.
For months, Ms. Taylor’s death has been a rallying cry. Michelle Obama and Kamala Harris, the Democratic vice-presidential nominee, called out her name during the Democratic National Convention. Oprah Winfrey paid for billboards demanding the officers be charged, writing in her magazine, “We have to use whatever megaphone we can.”
Rukmini Callimachi reported from Louisville and Frankfort, Ky., Nicholas Bogel-Burroughs from New York, and John Eligon and Will Wright from Louisville. Julie Bosman contributed reporting from Kenosha, Wis. Kitty Bennett contributed research.