New York, NY — A former Las Vegas casino security guard with a documented history of mental illness left five people dead, including an NYPD officer, after opening fire Monday evening inside a Midtown Manhattan skyscraper that houses some of the most powerful institutions in the country.

Shane Devon Tamura, 27, drove across the country from Nevada and arrived in New York City just hours before unleashing a brutal attack with an AR-15-style assault rifle at 345 Park Avenue — home to the NFL, Blackstone, and Rudin Management.

“He came here with one goal,” said NYPD Commissioner Jessica Tisch at a late-night press conference. “And it was carnage.”

Tamura, whose car was traced through multiple states in a two-day cross-country journey, pulled up in a double-parked BMW with Nevada plates near the intersection of 51st Street and Park Avenue. He exited the vehicle carrying a visible M4-style rifle, walked directly into the building’s lobby at 6:28 p.m., and began firing.

The first person he killed was Officer Didarul Islam, 36, a four-year veteran of the NYPD assigned to a private security detail at the building. According to Tisch, Islam had no time to react. He was shot point-blank and died instantly.

Tamura then turned his rifle on others in the lobby, gunning down a woman hiding behind a pillar and a security guard stationed at his desk. Another man was shot and critically wounded, while four more people sustained minor injuries fleeing the chaos.

As terrified workers ran for cover, Tamura calmly approached the elevators. Surveillance footage shows him allowing one woman to exit unharmed. He then rode to the 33rd floor — the site of Rudin Properties’ corporate offices — and continued his rampage. There, he killed a fifth victim before walking down a hallway and shooting himself in the chest.

By 7:52 p.m., Commissioner Tisch confirmed: “The lone shooter has been neutralized.”

Tamura’s motives remain unclear, but his past offers chilling context. According to Las Vegas law enforcement, he had a well-documented history of mental health issues and had previously been prescribed psychiatric medication. Police recovered that medication, a concealed firearm permit, and a backpack filled with ammunition and weapons inside his BMW.

One photo obtained by the New York Post showed the blood-smeared Palmetto State Armory AR-15 rifle used in the attack — a weapon equipped with a black scope, handguard, and shoulder sling. He also carried a loaded revolver and multiple magazines.

A former high school football standout in California, Tamura was once described in a local news interview as “quiet, polite, and driven.” What drove him to violence on one of the busiest streets in Manhattan remains the subject of ongoing investigation.

“There’s no indication, at least not yet, that this was terrorism-related,” said an NYPD official. “But the planning involved suggests this was not spontaneous.”

The attack stunned the city — and devastated the law enforcement community.

Officer Islam, who leaves behind a wife and two young children, was remembered by colleagues as soft-spoken and dedicated. “He gave his life protecting others,” Mayor Eric Adams said. “That’s the definition of heroism.”

As details emerged, reactions poured in from stunned witnesses.

“I was in the lobby when it happened,” said one building employee. “The guy just walked in, calm as anything, then started firing. It was a nightmare.”

Jessica Chen, attending a corporate presentation on the second floor, described chaos as gunshots rang out from below.

“We heard the pops — at least six in a row. People screamed, ran into conference rooms, shut doors. No one knew what was happening.”

Law enforcement sources say Tamura failed to report to work in Las Vegas on Sunday. His car was later seen on surveillance systems passing through Colorado, Nebraska, Iowa, and finally Columbia, New Jersey — where it was tracked at 4:24 p.m. Monday, just two hours before the massacre began.

Now, the questions multiply: Why that building? Why that day? And could it have been prevented?

Gun control advocates immediately seized on the tragedy to renew calls for stronger red-flag laws and national permit reform. But others pointed to mental health breakdowns and lapses in communication between states.

Senator John Kennedy of Louisiana ignited backlash online after commenting: “We don’t need more gun control — we need more idiot control.”

Whatever the political fallout, the human toll is undeniable.

A Midtown tower, once filled with executives and interns, now bears the scars of gun violence. Yellow police tape still flutters across Park Avenue. Security has been tripled. And inside Rudin Properties’ 33rd floor offices, blood stains mark the final steps of a man whose mind collapsed and took five lives with it.

The city will recover. But for the families of the dead — and the stunned survivors — nothing will ever be quite the same.