Terrifying photos show Blackstone employees barricading their office door with piles of furniture as gunman Shane Tamura rampaged through the Midtown building that houses their headquarters Monday night.

Workers in business attire were seen stacking dozens of gray couches up against their office door inside 345 Park Avenue — which also houses the NFL headquarters — until the furniture barricade reached the ceiling, according to the photos obtained by ABC7.

Panicked workers even began pulling apart wood desks to add more furniture to the barrier, the pics provided by a Blackstone employee showed.

A police officer and at least four other people were shot and killed — and several others injured — by Tamura, who stormed into the swanky skyscraper where the NFL also has its headquarters.

The 27-year-old maniac barged into the 44-story building armed with a Palmetto State Armory AR-15 and opened fire at around 6:30 p.m. during the evening rush, law enforcement sources told The Post.

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 then turned the gun on himself, cops said.

The 1,900,000 square foot skyscraper occupies an entire city block bounded by Park Avenue, Lexington Avenue, 51st Street and 52nd Street, according to its management company.