Family members are mourning a 16-year-old boy from Sheepshead Bay who was killed in a shooting that police say may have been accidental.

Julani Bannister said her younger brother, Ka’mardre Coleman, was not just her sibling, but her best friend. The 21-year-old said she had been looking forward to celebrating her upcoming college graduation with him.

“That’s my hype man," said Bannister. "We was hype about my graduation. We were about to recreate my high school graduation photo and all that, like, I’m so hurt, so angry."

But on Monday night, Bannister learned her brother was gone.

“I’ve been through a lot these last four years, but this right here is the worst thing [expletive] I've ever been through,” she said through tears.

Police said Coleman was visiting a friend inside a NYCHA building on Avenue X when he was shot in the chest. Police sources said another teen was handling a gun when it went off. Investigators believe the shooting may have been accidental.

Bannister pushed back on any suggestion that her brother was involved in the wrong crowd.

“My brother ain’t do none of that gang affiliated, nothing. I made sure as his older sister,” she said.

Police said one of the teens ran off after the shooting. A 16-year-old has since been arrested and charged with manslaughter, criminally negligent homicide and criminal possession of a firearm.

Still, Coleman’s family said they have many unanswered questions.

“Me being his auntie, I don’t feel like it was an accident," said Elixiss Oquendo, Coleman’s aunt. "I feel like there’s more to it and hopefully we’ll get to the bottom of it."

Coleman’s sister said he was deeply loved and remembered by the entire community. A memorial with candles and photos was set up outside the NYCHA building he lived in on Nostrand Avenue.

Bannister said her brother was on the right path. He was a good student, a star on the football field and on the basketball court, with plans to go to college.

“He wanted to say he’d be a cop detective," she said. "He was all about his community."

Coleman was a sophomore at United Charter High School for Advanced Math & Science III and played for the Sheepshead Bay Sharks. In a statement, school spokesperson Stephanie Millian wrote, "We are deeply saddened by the tragic loss of Ka’mardre Coleman, an incredible athlete, scholar, and friend,” the statement said. “This is an incredibly difficult time for our school community, and we extend our heartfelt condolences to his family, friends, and loved ones.”

Bannister said the loss has left a hole in her life.

“That’s my best friend," said Bannister. "I ain’t had nobody to talk to, I had him."