Police fatally shot a Brooklyn man during a shootout Friday morning after he barricaded himself in Bedford-Stuyvesant brownstone and fired several rounds that wounded an NYPD officer, NYPD Commissioner Jessica Tisch said.

The alleged gunman, Lamin Simmons, 48, died after being hospitalized, according to Tisch. The officer who was shot, Detective Matthew Gale of the emergency service unit, is in stable condition with an injured left leg.

Simmons’ wife and son told police he had a history of mental illness.

During a press conference, Tisch described a tense confrontation between police officers and Simmons inside a brownstone where multiple residents live. She said more than 20 rounds were fired by Simmons before the NYPD arrived at the scene.

Police officials said officers arrived at the home on Kosciusko Street between Marcy and Tompkins Avenues at around 5:46 a.m. after receiving a call from a neighbor who heard gunshots.

Tisch said the officers heard more gunshots when they arrived at the first floor apartment. She said they broke into the home, saw Simmons with a gun and then left the building to request additional support. During that time, Simmons’ wife and son escaped the home and spoke to the officers, Tisch said.

Tisch said a team of hostage negotiators tried to talk to Simmons. When they returned inside the building, police found him on the second floor where an elderly couple lives. Tisch alleged Simmons refused to drop his weapon, and started firing shots at the officers, at least one of which hit Gale in the leg. At least four officers opened fire on Simmons and killed him, according to Tisch.

An investigation is ongoing, but the police commissioner said officials believe the incident began as a dispute between Simmons and the elderly neighbors on the second floor.

Mayor Zohran Mamdani, who joined Tisch at the press conference, said he had visited the hospital and met with Gale’s wife. He expressed gratitude for his service.

Mamdani has called for reforming B-HEARD, a system that diverts some 911 calls to trained mental health professionals, but it is unclear when that program can be revamped. Only a small fraction of calls are eligible. Incidents involving violence and weapons do not qualify for B-HEARD.

The number of cases handled by B-HEARD have fallen over the year, although city agencies disagree on the extent of the decrease.

“When New Yorkers call 911 they expect someone to show up,” Mamdani said. “What this officer and so many others today did was exactly that.”