PHILADELPHIA (WPVI) -- A judge Tuesday upheld charges against a former Philadelphia police officer accused of shooting and killing a 12-year-old boy.
According to District Attorney Larry Krasner, this is the first time an officer who was on-duty is facing a first-degree murder charge in Philadelphia, a decision he said is supported by the evidence and was not made lightly.
Mendoza was one of four undercover officers conducting surveillance at 18th and Johnson streets in South Philadelphia on March 1.
The officers allege they saw two young males, including one identified as Siderio. One of them was holding a gun.
The officers drove toward the two males, stopped a few feet away, then activated the red and blue emergency lights on their unmarked vehicle, police say.
According to police, that's when the officers heard gunfire and the sound of glass shattering from the rear passenger window.
One of the officers was hit by shards of glass in his face and eyes. Police say the bullet went through the rear passenger window's glass, hit the inner doorframe, then went through the passenger's headrest before stopping in the vehicle's headliner. Philadelphia DA Larry Krasner said it was Siderio that fired at the car.
Two of the officers got out of the vehicle and fired at Siderio.
Police say Siderio was hit in his upper right back, with the bullet exiting from his left chest.
He was rushed to the hospital and pronounced dead a short time later.
According to the grand jury presentment back in May, Mendoza fired a total of three shots.
The first shot was fired near 18th and Barbara, and the second shot was fired after Siderio discarded his gun, the grand jury presentment stated.
That's when Siderio stopped running and went to the ground, either because he tripped or he was diving to the ground, according to the presentment.
Mendoza then approached Siderio without taking cover, Krasner said, in a way "completely inconsistent with Mendoza believing Siderio was armed."
The grand jury presentment says Mendoza was about 10 feet away from Siderio when he allegedly fired a third shot, killing Siderio.
Within a minute of the shooting, Mendoza allegedly told another officer that Siderio threw the gun, and pointed back to where it was located.
"Thus, when Mendoza fired the third and fatal shot, he knew the 12-year-old, five-foot tall, 111-pound Thomas Siderio no longer had a gun and no ability to harm him," Krasner said.
Mendoza's arraignment is scheduled for October 25.