A 12-year-old boy died Sunday after he was shot by Cleveland police while he carried an "airsoft" pellet gun.

A rookie officer shot the boy at a recreation center Saturday afternoon after a 911 caller reported "a guy with a pistol" on the rec center's swing set. The caller told the dispatcher the weapon was "probably fake," but the officer — who fired twice, hitting the boy in the stomach — wasn't informed of that critical detail, according to a statement made by Jeff Follmer, the president of the Cleveland Police Patrolmen Association's to local media.

"Besides, we have to assume every gun is real," Follmer said. "When we don't, that's the day we don't go home."

The shooting — at Cuddell Recreation Center on the city's west side — occurred just days after Cleveland cops killed an unarmed schizophrenic woman outside her house by slamming her on the slamming her on the pavement.

The Cleveland Police have killed two people in ten days. One, an unarmed woman and two, a 12 year old boy. — Nettie (@juhneda)November 23, 2014

The 12-year-old — whose name has not yet been released — lived right across the street from the rec center, his mother Samaria Rice told local media. Rice was home at the time of the shooting. Two men came to tell her what happened, but she said that when she ran to scene of the shooting police wouldn't let her pass. Rice said she could not understand why police would have shot her child.

The mother maintained that her son never had any kind of gun, saying he must have gotten it from a friend. Airsoft guns are a common type of replica pistol that fire small plastic or metal pellets. They often look very realistic, and images of the gun released to local media show that its orange safety indicator had been removed.

BB gun Cleveland police said a 12yo boy pulled from his waistband before they shot him. — Cory Shaffer (@cory_shaffer)November 23, 2014

The boy — whose name has not yet been released — was sent to Cleveland's MetroHealth Hospital to be treated for critical injuries. He underwent surgery, but died there Sunday morning.

The Cleveland Police explained on their blog that they'd asked the boy to "raise his hands" when they arrived at the recreation center.

"The suspect did not comply with the officers' orders and reached his waistband for the gun," the blog post said. "Shots were fired and the suspect was struck in the torso."

The boy neither verbally nor physically confronted the officer, Cleveland Police's Deputy Chief told cleveland.com.

The rookie officer and the officer who accompanied him — a cop with more than a decade of experience — have been placed on administrative leave, the Cleveland Police blog announced.

The Department's Use of Deadly Force Investigation Team is currently investigating the incident, and is also investigating the death of the unarmed schizophrenic woman.

The shooting sparked a wave of protest on Twitter, just minutes after the boy's announced death.

Anonymous Los Angeles posted a mock advertisement from the police that said, "don't worry! I investigated myself and found I did nothing wrong. Evolution of a police state."

But some Cleveland residents showed sympathy with the officers in their tragic mistake.

"Had they assumed it was fake, and it was real, this story would be a lot different," public relations professional Stephanie Lentz tweeted about the gun.

Others were even less sympathetic.

"I don't blame the cop one bit," one former Cleveland resident tweeted. "The kid messed with the bull. Got the horns."

Follow Meredith Hoffman on Twitter: @merhoffman