CHARLOTTE, N.C. — A North Carolina district attorney says no charges will be filed in the January shooting of a robbery suspect who was killed by a police officer.

• The department says it's impossible to show the officer didn't act in self-defense
• They say the robbery suspect ignored the officer's commands
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In a letter to Charlotte-Mecklenburg Police Chief Kerr Putney, Mecklenburg County District Attorney Spencer Merriweather III said his office determined that Officer Timothy Kiefer was justified in using deadly force when he shot 32-year-old Michael Daniel Kelley. The officer is white, as was Kelley.

The department said Kiefer shot Kelley after the suspect ran toward him and ignored the officer's commands. The statement also says investigators recovered a knife at the scene of the shooting.

Merriweather wrote that it would be impossible for prosecutors to show Kiefer didn't act in self-defense when he shot Kelley, who investigators say was involved in two armed robberies.