A federal grand jury has indicted a Louisville man on charges in connection to shooting at law enforcement officers serving a warrant for a kidnapping and murder case.Donald Simonton, 68, was charged with assaulting, resisting or impeding agents from the Bureau of Alcohol, Tobacco, Firearms and Explosives who were working with Louisville Metro police on a search warrant investigation, according to the U.S. Attorney's Office for the Western District of Kentucky.Federal investigators said Simonton fired multiple rounds at federal agents with the ATF's special response team as they made entry into his home on 41st Street in the Shawnee neighborhood. The law enforcement officers were serving the warrant in connection to the arrests of Roderick Bush and Dejuan Simonton for the September murder of Jermaine Sprewer.More on Sprewer case: Suspects charged in kidnapping, killing of Louisville 25-year-old arraigned in courtSimonton admitted to firing the shots because he told investigators that he didn't realize the police were at his door, according to police records.The 68-year-old man is also facing a charge of use of a firearm during and in relation to a crime of violence, the U.S. attorney's office said. He is due in court on the federal charges on Feb. 25.Continuing coverage: Judge sets bond at $250,000 for Louisville man accused of firing at officers during investigationAccording to a statement released Friday, Simonton faces a minimum of 10 years in prison.Simonton also faces state charges for the incident at his home. He was arraigned last week on charges of attempted murder and wanton endangerment of a police officer.In court, Simonton's public defender asked the judge to lower the bond because he doesn't have an extensive record and is retired with no way to pay a high bond.Judge Lisa Langford emphasized that the bond amount is high because the incident involved Simonton opening fire on law enforcement officers. Bond was set at $250,000.