A Delco teen was killed in an accidental shooting. He was to receive a Young Hero Award in D.C. next month.

At 17, Anthony Alexander Jr. was weeks away from being honored as a hero, a brave young man who had rescued three children from the freezing waters of a pond and pulled them to safety last February.

For that, the Congressional Medal of Honor Society was set to celebrate him at a ceremony in March. But on Sunday, Alexander was shot and killed in a Drexel Hill apartment when police say another teen who was playing with a Glock pistol accidentally shot him in the face.

Diamire Hickman, 16, has been charged with third-degree murder and involuntary manslaughter in Alexander’s death, a loss that has left the teen’s family shaken.

“He was a beautiful child, and this is still not real for me,” Alexander’s stepmother, Ava, said Tuesday. “He saw the good in everybody, and he would always come to someone’s defense.”

Alexander and Hickman were among a group of teenagers gathered in an apartment Sunday on Marshall Road in Drexel Hill, according to the affidavit of probable cause for Hickman’s arrest. Officers responding to reports of the shooting found Alexander sitting on a couch in the apartment, shot once in the face. He was pronounced dead at the scene.

Investigators tracked down several other teens who had been at the apartment at the time, who told them that Hickman fired the gun and fled, the affidavit said. Surveillance footage from the neighborhood showed Hickman hopping a fence near the apartment, holding a handgun.

Hickman turned himself in to police in Upper Darby on Monday and consented to an interview, the affidavit said. He told investigators the teens had been live-streaming themselves on Instagram in the apartment while “passing around” two handguns.

While holding the Glock, Hickman said, he “put his hand on the trigger a teeny bit,” causing the gun to go off and shoot Alexander, according to the affidavit. He then fled the apartment with the other teens.

Hickman remained in custody Tuesday, in lieu of $75,000 bail. There was no indication he had hired an attorney.

Alexander’s family, meanwhile, is reeling. The junior at Academy Park High School loved football, basketball, and karate, they said. After high school, he hoped to enlist in the Marine Corps, taking after his oldest stepsister, his stepmother said.

The last few weeks have been a blur of activity for the family, as they prepared for a trip to Washington. On March 25, Alexander was set to receive the Young Hero Award from the Congressional Medal of Honor Society, an accolade given to young people under 17 for exhibiting “courage in a dire situation.”

Alexander had been hanging out with friends in Collingdale Park last Presidents’ Day when three children who were walking on a frozen pond fell through the ice. The teen attempted to use a log to pull the kids to safety, but when that failed, he jumped into the frigid waters to grab them.

“They really need help,” he said at the time. “I wasn’t going to sit there and let them drown like that.”

With the help of a responding police officer, Alexander was able to rescue all of the children without injury. For his actions, he received a commendation from the Collingdale mayor and, eventually, a nomination for the national award.

U.S. Rep. Mary Gay Scanlon, a Democrat whose district includes Drexel Hill, honored Alexander on the House floor in May, saying that the teen’s “quick thinking and selfless action” prevented a tragedy.

Alexander had been looking forward to the trip to Washington in March, his family said, and was eager to meet the Medal of Honor recipients who would have hung the medal around his neck during the ceremony.

But that honor was not to be.

“We have to do something about the gun violence,” Ava Alexander said, choking back tears, “because we cannot afford to keep losing our teenagers.”