PHILADELPHIA (CBS) — A young father was gunned down in Philadelphia on the Fourth of July in 2017. More than five years later, Niam Johnson-Tate’s murder remains unsolved. His mother wants to make sure her son is not forgotten.

“Before we hanged up, he said, ‘I love you,’ and I said, ‘I love you more,'” Kimberly Kamara said.

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Kamara talks about that last phone call with her son, Niam Johnson-Tate, as sirens whirl in the background of our conversation outside her Germantown home.

It was July 4, 2017. Johnson-Tate was home. Kamara was out of town. Her phone rang.

“His girlfriend’s mother screaming, ‘Niam has been shot, meet us at the hospital,'” Kamara said.

Johnson-Tate was first brought to Roxborough Memorial, but the 23-year-old was in bad shape.

He had been shot several times outside the home on Moylan Street.

Johnson-Tate was transferred to Temple University Hospital by the time Kamara and her husband were racing to meet him at the emergency room. She remembers seeing the ambulance pull up.

Medics were frantically working on her son.

“I broke through the crowd. I was able to touch his foot, and I’m hollering Niam, Niam, and I’m getting no response,” Kamara said. “And I just fall.”

Tests showed barely any brain activity.

Johnson-Tate was pronounced dead the following day, July 5, 2017.

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“He was an organ donor. That was the decision he made, and he was actually able to save seven people’s lives,” Kamara said. “I am so proud because he and I went back-and-forth about him having it on his driver’s license.”

Not three months before Johnson-Tate’s fatal shooting, a defining moment came in his life, mom says, the birth of his son. It changed him from a child into a grown man, and she adds he was scared.

“He took so much pride. The baby, I think was 2 or 3 days old, he was taking the baby around to see everybody,” Kamara said, “and I was like if you don’t get this baby back in the house … so he was really proud. But he didn’t know what he was doing.”

This mom says tragically, her family isn’t alone in processing the toll of gun violence. She says 10 to 12 people that he knew have been murdered.

That’s a staggering statistic. How does she reconcile that?

“I don’t. I just reach out to their parents if I can and talk to them,” Kamara said.

Who shot and killed Niam Johnson-Tate?

The case has idled and investigators are seeking new information.

“We have to take our homes back. No parent should be afraid of their children,” Kamara said.

Call 215-686-TIPS for the Philadelphia Police Department. There is a $20,000 reward.

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“It’s a part of me that’s not here, it’s a part of me that’s with my son,” Kamara said.