PITTSBURGH (KDKA) — Investigators are releasing new details today in the case against the man charged with homicide in the shooting death of an off-duty Pittsburgh Police officer last month in Homewood.

Christian Bey is charged with criminal homicide, carrying a firearm without a license, possession of a firearm without a license and persons not to possess, use, manufacture, control, sell or transfer firearms.

Allegheny County District Attorney Stephen Zappala has informed the court that the Commonwealth will seek the death penalty against Bey.

(Photo Credit: KDKA)

The District Attorney’s Office says it is seeking the death plenty for three main reasons:

  1. Officer Hall was a peace officer and public servant,
  2. Bey allegedly committed the killing during a felony,
  3. Bey allegedly created a grave risk of death for other people.

Investigators say Bey is responsible for the fatal shooting of off-duty Pittsburgh Police Officer Calvin Hall in Homewood back on July 14 during a block party on Monticello Street.

Officer Hall was rushed to UPMC Presbyterian Hospital, but died on a few days later on July 17.

The Allegheny County Medical Examiner’s Officer determined Officer Hall died from gunshot wounds to his back and ruled his death a homicide.

WATCH: KDKA’s Meghan Schiller reports from the studio.

Authorities have also unsealed the criminal complaint in the case. Investigators say they asked for it to be sealed so as not to alert the suspect or compromise the investigation.

The criminal complaint says: “Premature disclosure of the contents of this affidavit and related documents may have a significant and negative impact on the continuing investigation and may severely jeopardize its effectiveness.”

Detectives interviewed four key witnesses who were there when Officer Hall was shot.

According to the criminal complaint, it all began with a confrontation between Officer Hall’s cousin and some people at party. Police say family member called Officer Hall to their house to help get control of the situation.

Police say Officer Hall had been at the scene before that confrontation began, but decided to leave. One of the women, who police say was intoxicated, tried to block his vehicle from leaving the street. The criminal complaint says while trying to get the woman off of the street, Officer Hall was seen by witnesses arguing with Bey.

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Upon being called back and returning to the scene, police say Officer Hall apologized, including to a woman identified as Bey’s mother. However, that apology was apparently not accepted by the group.

The criminal complaint reports the shots rang out soon after. Police say one witness reported the gunfire coming “in close proximity of the group,” and seeing Officer Hall fall to the ground.

Police said they used surveillance cameras to help track the suspect.

According to police, a camera on Brushton Avenue recorded a man – who was walking with a “distinct limp” – running from the area. A police dog was brought in and recovered a .45 caliber pistol in the yard of an abandoned home on a nearby alleyway.

The weapon’s hammer was cocked back, and the serial number was “obliterated” and unable to read, investigators said.

Other witnesses were able to identify Bey by his clothing and characteristics in the surveillance footage.

Police say Bey did not have a permit to carry a concealed weapon and was not allowed by law to be in the possession of any firearm.