A New York City police officer was indicted by a grand jury Tuesday for the fatal shooting of an unarmed man in a darkened stairwell of a housing project last November, the Wall Street Journal reported.

Officer Peter Liang, alongside his partner, was patrolling the stairwell in the Louis H. Pink Houses, a Brooklyn housing project around 11:15 p.m. on Nov. 20, 2014. The officers were conducting what is known as a “vertical patrol.”

While in the stairwell, Liang fired a single bullet, killing Akai Gurley, 28, who was in the stairwell a flight below with his girlfriend.

According to the New York Daily News, Deputy Inspector Miguel Iglesias had ordered his officers not to conduct these “vertical patrols” and was furious upon hearing that the officers had disobeyed his order.

Vertical patrols were the subject of a federal class-action lawsuit, which alleged residents of buildings belonging to the New York City Housing Authority were stopped by police without reasonable suspicion and in a racially discriminatory manner.

After news of the shooting came out, New York City Police Commissioner Bill Bratton was quick to say the shooting was an accident and admitted that Gurley was a “total innocent.”

However, reports emerged that instead of calling for help, Liang texted his union representative. Liang and his partner were out of contact for more than six and a half minutes after Liang fired his gun. Only after communicating with his union did Liang report the “accidental” discharge of his weapon.

Kenneth Montgomery, a lawyer for Gurley’s parents said the officer's actions constituted “criminal negligence.”

The criminal charge or charges Liang will face were not immediately clear, the Journal said, citing unnamed sources in its report.

The death of Gurley, who was black, followed other incidents of police involvement in the deaths of unarmed black men in New York and Missouri that sparked waves of national protests.

Liang and the City of New York are facing a US$50 million lawsuit over the death of Gurley, filed by his girlfriend Kimberly Ballinger.