Fatal accident.

Broward sheriff's deputies investigate the scene of an accident in the 4700 block of Southwest 33rd Avenue in Dania Beach. (Mike Stocker / Sun Sentinel / April 26, 2014)

UPDATE: The Broward Sheriff's Office on Sunday morning identified the boy who died as Xavier Crawford, 4, of Dania Beach. The driver was identified as Michael Reshick, 52, of Dania Beach.

The boys zipped on foot scooters outside their homes, just a stone's throw from what promised to be a delightful kids' birthday party, complete with balloons, a bounce house and water slide.

But the celebratory day instantly turned tragic on the residential street Saturday, when a green truck backed up from a parking space and ran over one of the three boys, a 4-year-old, causing him to suffer head trauma and other injuries, officials said.

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The eldest of the boys, 14, watched as it happened.

"No!" he screamed.

About an hour later, at 2:30 p.m., the 4-year-old was pronounced dead at the hospital.

Nicholas Johnson, 14, said he was with the child and the child's 10-year-old brother, waiting for the birthday party to start at the end of the block. When his friend was hit, he said he screamed out to the driver, telling him he had just hit the boy.

"I told him to stop," he said. "I said, 'no!'"

The 4-year-old's godmother, Matilda Douglas, said she was returning home from the supermarket when she saw the blood on the sidewalk. She saw the 4-year-old's mother holding her elder son, she said.

When Douglas realized what had happened, she said she dropped her grocery bags in disbelief.

"I said, 'oh my God,'" she said. "I just plopped down — boom. He was a cute little guy — a good little guy. He had a lot of sense."

Douglas said she had lived with the family for about two months. The little boy, who would've been 5 in June, she said was extremely smart and genuinely cared about the well-being of his family members.

"He would come in my room and say, 'Matilda, did you take your medicine?'" she said. "It makes me so emotional. It makes me feel sad because I feel like he loved me."

Authorities haven't released the boy's name.

When the accident happened, the driver of the vehicle got out of the truck immediately and called 911, sheriff's spokeswoman Gina Carter said.

The man is cooperating with deputies, she said.

Douglas said she went over and talked to the driver after the accident happened. He told her he felt extremely bad about the tragedy, she said.

Saturday's birthday party, in a grassy area at the end of the block, was meant for a little girl who lived in the row of duplexes — the same duplexes the 4-year-old boy lived in. Partygoers said everyone in the block was coming, though many said they didn't know the boy or his family.

A few partygoers said a lot of people came to the party after the accident happened and didn't see anything. Parents were worried their children would find out the boy had died, they said, so they opted to let the kids continue playing and break the news to them later.

As the kids ran around in bathing suits, parents somberly looked at the accident site.

Johnson's mother, Brooke Davis, said she was heartbroken and shocked by the tragedy. The boy and his family had just moved into the neighborhood, Davis said, and her son played with the boys often.

She arrived on the street to find it blocked off by deputies and feared the worst. Davis, Johnson and her oldest son, Andrew, live next door to the boy and his family.

As the boy's mother and older brother were being taken to the hospital, she hugged the brother and told him it would be all right.

"I told him that it would be fine, and [the boy] would survive," she said. "And it wasn't. He didn't."

She said children are constantly playing in the street in their neighborhood.

"This scares the hell out of me," she said. "It could've been my son."

kjacobson@tribune.com, 561-243-6547 or Twitter @katejacobson