The bloodstained assault rifle used by gunman Shane Tamura during his deadly rampage inside a Midtown skyscraper Monday night is shown in shocking detail in photos obtained by The Post.

The Palmetto State Armory M4 assault rifle used in the shooting that killed an NYPD cop and three civilians is .223-caliber and is equipped with a black scope, a handguard, and a shoulder sling.

The AR-style gun retails for around $500 and was equipped with a high-capacity magazine. 

Photos show the green handguard of the rifle soaked in blood on the carpet in a 33rd-floor office inside 345 Park Ave., where the 27-year-old carried out the rush-hour mass shooting.

The NYPD found a loaded revolver, ammunition, magazines, and a rifle case with rounds in a black BMW that Tamura double-parked outside the Midtown skyscraper, NYPD Commissioner Jessica Tisch said at a press conference Monday night. 

The car, registered in Nevada to Tamura, also contained a backpack and prescription medication, the commissioner said.

The gun appears to have a 30-round magazine.

A concealed firearms permit from Las Vegas, Nevada, was found at the scene with a photo of the suspect and his name. The permit was issued in July 2022, according to the photo.

How the shooting unfolded

• Reports of the shooting at 345 Park Ave. start coming in around 6:28 p.m.
• Shane Tamura, 27, is seen getting out of a black BMW between 51st and 52nd streets with an M4 rifle.
• He enters the lobby and turns right, where he shoots police officer Didarul Islam, 36, dead.
• Tamura guns down a woman cowering behind a pillar in the lobby, sprays more bullets and walks toward the elevator bank — where he shoots dead a security guard crouching at his desk.
• One more man reports being shot and injured in the lobby. He was in critical but stable condition.
• The gunman allows a woman to walk out of the elevators unharmed before heading up to the 33rd floor, where building owner Rudin Properties’ offices are located, “and begins to walk the floor, firing as he traveled.”
• One woman is shot and killed on that floor before Tamura shoots himself in the chest.
• It’s unclear how long the mayhem lasted. Police Commissioner Jessica Tisch posted on X at 7:52 p.m.: “The scene has been contained and the lone shooter has been neutralized.”

Tamura unleashed a “barrage of shots” with the assault rifle, which witnesses said sounded “like an automatic weapon” — killing five people and injuring several others in the violent spree that began around 6:30 p.m.

After shooting several people in the building lobby, Tamura fatally shot NYPD officer Didarul Islam, who was working a paid security detail and sitting near the elevator banks of the office building.

Tamura allowed a woman exiting those elevators to leave unharmed.

He shot and killed a person on the 33rd floor of the building, which houses the headquarters for Blackstone and the NFL, before turning the gun on himself.