The two police officers who were shot and wounded at a public housing complex on East 156th Street in the Bronx on Thursday night were conducting a vertical stairwell patrol, according to the NYPD. The alleged gunman, identified as 23-year-old Malik Chavis, apparently killed himself soon after the shooting, in an apartment one floor from the scene.

The shooting took place around 8:00 p.m. at 320 East 156 Street within the NYCHA-run Melrose Houses in the South Bronx. According to the police, three officers were in the 6th floor stairwell conducting a routine patrol when they encountered Chavis and another man.

The men were reportedly drinking beer. When the officers asked them for identification, Chavis said he did not have his ID.

The News reports that Chavis was holding a duffel bag with a sawed-off shutgun zipped inside. He allegedly told the officers he was heading upstairs to get his ID before turning back and firing three shots in the sixth floor stairwell.

Officer Patrick Espeut, 29, was hit in the cheek, and Officer Diara Cruz, 24, was hit in the abdomen. Both are expected to survive.

Espeut and Cruz each have two years of experience on the force, according to the NYPD, and are part of Police Service Area 7, the unit that patrols public housing within the NYPD's 40th and 42nd precincts.

Sources told the NY Times that the officers shot back, one of them once and the other twice, although this information was not confirmed by the NYPD. The NYPD did confirm, however, that the stairwell where the officers encountered the two men was illuminated.

Chavis ran from the stairwell into an apartment on the 7th floor after the shooting. Additional responding officers entered the apartment, where they encountered Chavis dead, apparently by a self-inflicted gunshot wound. Upon entering the apartment he allegedly said, "I'm about to die; get out of the room."

Chavis was a Bronx resident, but did not live in the Melrose houses, according to CBS. He was apparently visiting his girlfriend on Thursday night, who lives in the houses. The news outlet reports that Chavis had 17 prior arrests.

There were several other people in the apartment where Chavis was found, and four of them were taken to the 40th Precinct for questioning, including the other man encountered in the stairwell. A semi-automatic firearm and a shotgun were recovered from the scene, according to the NYPD.

Asked on Thursday night why these individuals were being questioned since the shooter was dead, Chief of Detectives Robert Boyce said that the other individuals had "allegedly done nothing" and "they're not being held for anything [other] than purely giving information."

One witness saw the officers being escorted from the building after the incident. "She was holding her chest as they took her out on a stretcher," witness Kendrick Joseph told the News. "It looked like her vest caught it. Her pant leg was ripped open and she was bleeding from it. The male cop’s head was wrapped and he was covered in blood. ... I don’t know how he was alive.”

Mayor de Blasio arrived at Lincoln Hospital shortly after the shooting, having just delivered his State of the City address at nearby Lehman College. "I’m pleased to say both officers have been alert and communicating," he told reporters. "Both very early in their work on the force. Both two years on the job, but doing their job, going out there, keeping people safe, and running into some bad guys, but, thank God that first responders came to their aid."

Police Commissioner Bratton was not at the hospital on Thursday night, but tweeted, "Proud of my officers, hopeful for their speedy recovery, grateful for the many expressions of concern and support on their behalf."

Chavis' father told the NY Times on Thursday night, "He [my son] had a heart just like everybody else, he had a mind just like everybody else. As far as what happened or what's going on, I don't know. I don't have much to say."

Last night's shooting comes in the midst of the trial for Peter Liang, the NYPD officer who shot and killed 28-year-old Akai Gurley in a darkened Brooklyn stairwell in November 2014 while conducting a similar vertical patrol. Gurley was unarmed and, in the words of Commissioner Bratton, "a total innocent."

Over the course of the trial, NYPD officers have testified that patrolling NYCHA buildings is considered particularly dangerous within the department. For their own part, residents of the Pink Houses told us this week that they don't think policing tactics around their homes have improved since Gurley was killed last February.