Former Philly cop pleads guilty to murder in shooting death of 12-year-old boy

According to ABC 6, authorities claimed that Siderio was with an unnamed 17-year-old during the incident. The officers drove their car over to question the two during a firearm investigation. Police also claimed that Siderio then shot at the car before he ran away and ditched the gun.

The officers reacted by shooting at the boy before Mendoza began chasing the 12-year-old down the street. He then shot at the boy twice with one striking him in the back from "relatively close range."

In a press conference, Philidelphia district attorney Larry Krasner said that the officer knew the boy was unarmed and had "no ability to harm him" when he fired the fatal shot.

"Justice must be evenhanded,” the district attorney's office told the New York Times. "Everyone must be accountable under the law.”

In a statement to ABC 6, Siderio's family said the officer should have been charged with first-degree murder, and they were unhappy with the plea agreement.

Siderio's aunt, Joanne Payne, said, "It's heartbreaking, it's earth-shattering, it's devastating. They got it wrong." She added, "He should be held to a higher standard than you and I."

"We cannot stand over a child on a city street and shoot them. TJ was on the ground, face down, unarmed. The threat was eliminated," Payne noted. "They painted a picture of a horrendous crime, and the sentencing that they are offering is nowhere near the balance of the scale."

Mendoza served on the force for five years before the incident, where he was terminated the week after the shooting. Then Police Commissioner Danielle Outlaw said that the incident and the conduct of Mendoza were a violation of the department's policy.

Mendoza will face sentencing in July.