(CNN) Prosecutors in Kentucky have filed a motion to drop attempted murder and assault charges against Kenneth Walker, the boyfriend of slain EMT Breonna Taylor, according to Commonwealth's Attorney Tom Wine.
Police say Walker fired at them during a narcotics investigation in March when three officers forcibly entered Taylor's apartment to serve a search warrant. Taylor was shot at least eight times.
The raid left Taylor dead and Walker was charged with attempted murder of a police officer and first-degree assault.
Walker's attorney, Rob Eggert, filed a motion on Thursday to have the charges against his client thrown out.
Wine maintained there had been neither misleading testimony by the detective in this case nor any ethical breaches, as Walker's attorney claimed, but the prosecutor said, "more should have been presented to the grand jury, including the statement of Kenneth Walker."
"I believe that additional investigation is necessary, I believe that the independent investigation by the Attorney General's Office of Kentucky, the FBI, and the US Attorney's Office must be completed before we go forward with any prosecution," Wine said. "If after those reviews, we believe there is sufficient evidence to present this matter to the grand jury, we will do so. And if he wishes to testify before the grand jury, Kenneth Walker will be given that opportunity."
During the raid in March, Taylor was shot at least eight times when three officers forcibly entered her Louisville apartment to serve a search warrant in a narcotics investigation. The department said the men announced themselves and returned gunfire when Taylor's boyfriend fired at them.
But in a wrongful death lawsuit, Taylor's mother says the officers didn't knock at all and should have called off their search because the suspect they sought had already been arrested.
Officers didn't find drugs in her apartment when they entered, Taylor's mother said in the lawsuit.
Since the shooting, several developments have happened.
The FBI has opened an investigation. The Louisville Metro Police Department said that it would require all sworn officers to wear body cameras. None of the three officers who entered Taylor's apartment wore body cameras, the department said, since they were plainclothes narcotics officers.
Going forward, "no-knock warrants," which allow police to enter a residence without announcing themselves or their purpose, must be signed off on by a judge and the police chief or his designee before police can serve them. Previously, the warrant required only a judge's sign-off.
They're the first steps toward improving police accountability, Mayor Greg Fischer said earlier this week at a news conference, in which he repeatedly referred to Taylor's death as a "tragedy."