Story highlights Police Officer Lisa Mearkle faces homicide charge for shooting an unarmed man

David Kassick, 59, was shot and killed after fleeing a traffic stop

(CNN) The emissions sticker on David Kassick's car was expired.

That's what first caught the attention of Lisa Mearkle, a police officer in Hummelstown Borough, Pennsylvania, who ordered Kassick, 59, to pull over on February 2.

Instead, Kassick fled. Moments later, he lay dead on the ground in a yard near a relative's home.

On Tuesday, Mearkle was arrested on a homicide charge following a state police investigation into the shooting.

Mearkle's attorney, who described the use of deadly force in the case as justified, said he is girding his client for national scrutiny as the case finds itself on a growing list of officer-involved shootings.

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