HASSAN COX is a big brother, a 12-year-old who takes seriously the responsibility of watching over his younger siblings.

After school, he wrangles with his sisters and brothers, even if their mother is usually there to greet them. He holds tight his younger charges' hands as they cross the busy streets.

And so when a hit-and-run driver killed his little sister, Jayanna Powell, on Nov. 18 - ripping her 8-year-old hand from his as they crossed at the corner of 63rd Street and Lansdowne Avenue in Philadelphia - that unconscionable driver not only cut short the life of an innocent girl, he also left a boy to grapple with guilt no child should ever have to carry.

"I was holding her hand," he says.

Hassan told his mother exactly that right after the accident. At the hospital, when she told him and his siblings that their sister was gone, he sobbed:

"Mommy, I'm sorry. Mommy, I couldn't protect her. I'm sorry."

Weeks later, the words from the quiet, tall and handsome boy still deliver the same gut punch.

Of course his mother, Ayeshia Poole, told him he wasn't to blame. "You know it's not your fault, right?" she repeated as I sat with them one recent day.

There was nothing he could have done to slow down the car that sped through the intersection to beat a yellow light. Nothing the big brother could have ever said or done would make his adoring little sister think he was anything but a hero to her.

Hassan nods and says he understands, but his eyes betray pain and doubt, and a lingering memory of feeling his little sister's hand slipping from his or seeing her being thrown by a car.

His mom says he's doing better.

It's taken time - it will take more, and therapy, which the family is all getting. But Poole also credits a growing relationship with police officers from the 19th District who have claimed the family as their own.

Police eventually charged Paul Woodlyn in the hit-and-run death. But before a suspicious body shop owner alerted police, the family held marches to mourn Jayanna's senseless death and call attention to the crime.

It was at one of those marches that Poole leaned into Philadelphia Police Officer Frank Gramlich and told him that Hassan was struggling. Gramlich, who has a son around Hassan's age, didn't hesitate.

Police officers reacted as if they had lost one of their own.

"That's because we did," said Capt. Joseph Bologna.

As Poole recalled how Bologna marched alongside her and her family as they sought leads in the days following the accident, she still can't quite believe it.

"In a million years, I would never have guessed that one day I would be walking down the middle of a street with an officer screaming louder than anyone for justice for my little girl," she said. "I'll never forget it."

Both officers have been around long enough to know it's not healthy to take cases home with you, no matter how hard they hit you. But they couldn't help it, especially after meeting Hassan.

"Just to see a kid who tried everything he could, to be doing the right thing and have something this horrible happen. It hit home," Gramlich said.

The day Poole told him about Hassan, he pulled him close and told him: "As a big brother, you did everything you could do. Don't blame yourself. It is not your fault."

He also told Hassan and Poole that they could call on him anytime.

"You're family now," he told the boy and his mother.

Poole thanked him and felt he was sincere, but was still surprised when she heard from him the next day. He and Bologna kept checking in, even after the driver was arrested.

They showered the kids with Christmas gifts, gave Hassan tickets to a Sixers game. Anything the family needed, they were on hand to help.

Before Jayanna's funeral, the officers came to the house and presented Hassan with dog tags, one etched with the word Hero, another with Jayanna's name.

During the funeral, the officers couldn't help but notice how Hassan rubbed the dog tags between his fingers.

Hassan's got a long road ahead of him, Bologna said. So do his mother and his siblings.

"But we're a family now," Capt. Bologna said. "And like a family, we're going to stick around way after everyone else goes home."

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