A 13-year-old boy was shot and killed in Chicago on Sunday as he recorded a physical fight that started over Facebook posts.

Officials say that Anthony Diaz followed his two older sisters, age 16 and 17, as left their home around 10 p.m. Sunday night to meet up with other girls to settle a dispute that began on Facebook. However, while he was recording his sisters fight with his cellphone, he was fatally shot in the chest, reports PEOPLE.

"It would never cross your mind that something like this would happen," his stepfather Ralph Otero told the Chicago Tribune. "We don't really know what happened."

Police say the young teen was shot in the chest as he was walking with a group.

According to the victim's sister, Diaz wanted to back her up in a fight with other girls over a Facebook post.

"We came, we fought. They just got out of hand. They jumped all of us and they ended up shooting my brother," said Jennifer Sosa, the victim's sister.

Otero said he had a bad feeling on the night of the shooting and felt uncomfortable with his children leaving the house so late at night.

"I said, 'Look, they're going in and out, I don't know what's going on. But I don't like the idea of them stepping out that late,'" he said.

Shortly thereafter, his wife received a phone call from her daughter expressing the bad news.

"(Anthony's mother) was telling me, 'They shot Anthony, they're telling me they shot Anthony.' So when I got there, he was already laying on the ground," Otero said. "And the paramedics were working on him.

"When I got there," Otero added, "I knew it would be bad. ... They said they shot him over seven or eight times. They came right next to him, and I guess when he fell, they came and kept on shooting."

Anthony was pronounced dead around 11:30 p.m. at Mount Sinai Hospital.

Police began interviewing witnesses and the victim's family on Monday.

"I loved him with all my heart," said the boy's mother, Laura DeDomenico. "I don't know what I'll do without him. The rest of my life, until I die, I will cry. A part of my heart is missing."

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