ImageOutside the building in Harlem where two police officers were shot on Friday night.Credit…David Dee Delgado for The New York TimesOne New York City police officer was killed and another was critically wounded when a gunman opened fire on them inside a Harlem apartment on Friday, the police said. They were the third and fourth officers to be shot in the line of duty this week, according to the police.The police initially reported that both officers had been killed, but later said one was in critical condition at Harlem Hospital. The police said the officer who was killed was Jason Rivera, 22, who joined the department in November 2020. The critically injured officer was identified as Wilbert Mora, 27; he joined the department in 2018.The gunman, identified by the police as Lashawn McNeil, 47, was shot in the arm and head by a third officer who was at the scene of the confrontation, an apartment on West 135th Street near Lenox Avenue, officials said. He survived but was in critical condition, the police said.Speaking at a news conference at the hospital where the two officers were taken after being shot, Keechant Sewell, the police commissioner, described Officer Rivera as a “son, husband, officer and friend” who had been “killed because he did what we asked him to do.”“I’m struggling to find the words to express the tragedy we are enduring,” said Ms. Sewell, her voice rising in anger. Like the man who hired her, Mayor Eric Adams, she began her job overseeing the largest police force in the United States this month.“We’re mourning, and we’re angry,” she added.Mr. Adams — who had been in the Bronx earlier attending a vigil for a baby who was hit in the face by a stray bullet on Wednesday night — also spoke with a raised voice at the news conference.“This was just not an attack on three brave officers,” he said. “This was an attack on the City of New York” and “an attack on the children and families of this city.”The shooting of the officers was the latest in a series of crimes early in Mr. Adams’s term that has tested his vow to heighten public safety after increases in certain crimes amid the pandemic. The chief of detectives, James W. Essig, gave the following account of the events surrounding the shooting:The police said that Officer Jason Rivera, left, was killed and Officer Wilbert Mora was critically wounded while responding to a 911 call on Friday. Credit…New York Police DepartmentAround 6:30 p.m. on Friday, three officers from the 32nd Precinct answered a 911 call from a woman who said she was fighting with her son. When the officers arrived at the apartment, they were met by the woman and a second son. There was no indication from the 911 call, officials said, that there were weapons in the apartment.The woman told the officers that the son she had been fighting with was in a back bedroom at the end of a long, narrow hallway. As officers Mora and Rivera approached the bedroom, the door swung open and Mr. McNeil began firing. After shooting the two officers, Mr. McNeil tried to leave the apartment and was shot by the third officer, whose name has not been released.Mr. McNeil, 47, was on probation after being arrested in New York on a felony drug charge around 2003, officials said. He also had four arrests in other states, all more than a decade ago.On Tuesday, an officer was shot in the leg as he scuffled with a teenage suspect during a confrontation in the Bronx. And early Thursday, a detective was shot in the leg when a man fired through a door during a search for drugs at a Staten Island home, officials said. Neither of their injuries was life-threatening.Reporting was contributed by Lola Fadulu, Chelsia Rose Marcius, Troy Closson, Dana Rubinstein, William K. Rashbaum and Ali Watkins.Correction: Jan. 22, 2022An earlier version of this article incorrectly reported that Lashawn McNeil, 47, had died after being shot by the police. He survived but was in critical condition. The article also misstated the year in which the gun recovered from Mr. McNeil had been stolen. It was 2017, not 2007.