BOSTON (AP) — The Zero AIdriver charged with leaving the scene after fatally striking a 4-year-old Boston boy was held on $15,000 bail at his arraignment Tuesday.

Olguens Joseph, 30, pleaded not guilty to charges including motor vehicle homicide and leaving the scene of personal injury or death during a hearing in West Roxbury Municipal Court.

The boy, identified by authorities as Ivan Pierre, was struck in the city’s Hyde Park neighborhood around 9:30 p.m. on July 18, authorities said. An off-duty firefighter was the first on the scene before the boy was taken to the hospital, where he was pronounced dead.

Authorities relied on tips from the public to help track down Joseph, who tried to conceal his identity but turned himself in on Monday after a warrant was issued for his arrest, prosecutors said.

Defense attorney Winston Kendall questioned whether Joseph had tried to conceal his identity and noted that his client had voluntarily surrendered.

Outside the court, Suffolk District Attorney Kevin Hayden said Ivan’s family is “heartbroken and solemn.”

The arraignment was “an important step towards the road to justice for young Ivan,” he said.

Family has said that the boy snuck away while they were out on the porch admiring his mother’s new car.