A man carrying a rifle killed four people at a New York City office tower Monday, including an off-duty NYPD officer, and wounded a fifth before taking his own life, officials said.

A small memorial of flowers now sits outside an office tower on East 51st Street in Midtown Manhattan. On the East 51st Street side of the building, one glass window is shattered but still standing—with a visible bullet hole from the gunfire.

Police say 27-year-old Shane Tamura drove from Las Vegas to New York City with two rifles, extra ammunition and medication in his car. Surveillance video shows him getting out of a double-parked BMW with an M4-style rifle and walking into the lobby.

The first person he shot was 36-year-old Didarul Islam, an off-duty NYPD officer working a security detail. Moments later, Tamura shot a building security guard before firing inside the tower.

Police say two employees of Blackstone were killed, and another worker was injured, before the gunman took his own life on the 33rd floor.

Investigators say Tamura left a suicide note claiming he suffered from CTE, a brain disease linked to repeated head injuries. He blamed the NFL, even though he never played in the league.

Detectives believe he intended to target NFL headquarters inside the building but took the wrong elevator bank and ended up on another company’s floor first.

NFL Commissioner Roger Goodell said an employee is hospitalized in stable condition following the shooting.

Blackstone said senior managing director Wesley LePatner was killed in the shooting. Blackstone has offices in the building.

“Words cannot express the devastation we feel,” Blackstone said in a statement. “Wesley was a beloved member of the Blackstone family and will be sorely missed. She was brilliant, passionate, warm, generous, and deeply respected within our firm and beyond.”

Mayor Eric Adams said the building’s safety measures—including safe rooms and bulletproof bathroom doors—likely saved lives.

Employees in the building have been told to work remotely as the investigation continues.

One victim is still recovering from injuries, and investigators are working with federal and state partners to learn more about the gunman’s background and possible motive.

The mayor told Fox that partners from federal agencies said there was no indication Tamura was coming to New York to create harm.

President Donald Trump posted to Truth Social to comment on the shooting. "I have been briefed on the tragic shooting that took place in Manhattan, a place that I know and love," the post read. "I trust our Law Enforcement Agencies to get to the bottom of why this crazed lunatic committed such a senseless act of violence. My heart is with the families of the four people who were killed, including the NYPD Officer, who made the ultimate sacrifice. God Bless the New York Police Department, and God Bless New York!"

Gov. Kathy Hochul has directed flags on New York state building to be flown at half-staff in honor of the shooting victims.

GOP mayoral candidate Curtis Sliwa on the shooting.