Updated

A white police officer who shot an unarmed, black teenager in the bathroom of his New York City apartment is expected to offer his first public account of the slaying on Friday at his department disciplinary trial.

Officer Richard Haste initially faced a criminal manslaughter charge in the 2012 death of 18-year-old Ramarley Graham, but the case was dismissed because of a procedural error. A new grand jury refused to indict.

Police department attorneys are now arguing that Haste should be fired.

The officer's lawyers say he shot Graham because he mistakenly believed he had a gun.

An administrative judge hearing the case will recommend a punishment to the police commissioner.