The man accused of running down two young boys on a motorbike in Southeast Washington last week was warned minutes before the accident to be careful around children, prosecutors said in court documents filed yesterday.

The warning came from a person who was walking the boys and other children to a day-care center, prosecutors said. The driver, Christopher D. Powell, smirked and drove off -- and a few minutes later, struck the two boys, they said.

Powell, 29, appeared in D.C. Superior Court yesterday and was ordered held without bond on a charge of second-degree murder in the death of 5-year-old Lawrence Yelverton. A 4-year-old boy remains hospitalized with injuries.

The court appearance came as D.C. Mayor Anthony A. Williams (D) and other officials called for stricter laws to control motorbikes and all-terrain vehicles. Neighborhood residents said they have repeatedly complained about speeding motorbikes in the area.

The accident took place about 3:50 p.m. Oct. 28 on a paved walkway in a courtyard of an apartment complex in the 2700 block of Langston Place SE. Prosecutors said Powell was 319 feet from the nearest street -- and 50 feet from a playground -- when he hit the children. After the accident, he left the scene. The motorbike was found, abandoned, a short time later.

Powell, of the 2300 block of Green Street SE, turned himself in late Wednesday after police announced that they had a warrant for his arrest. Court records show that he was on parole after serving time in prison for a 1999 conviction on charges of assault with a deadly weapon and carrying a pistol without a license. He also was convicted twice during the 1990s of attempted unauthorized use of a vehicle, records showed.

Powell's driving privileges were suspended before the accident, according to the charging papers. They provided no details about what led to the suspension.

The documents said Powell called police Saturday and told an investigator that he drove the motorbike. "He stated that he saw the children and attempted to stop but could not do so," the charging documents said.

Police examined the motorbike and found no mechanical defects, according to the court papers. Police also found no evidence to suggest that the driver attempted to brake, the charging papers said.

Police Commander Joel Maupin, who heads the 7th District, credited residents with alerting police to Powell's identity.

"Anytime you have a small child killed like that or hurt badly, even in your toughest neighborhoods, a lot of people will come forward and give you information," he said.

Speaking at his weekly news conference, the mayor called Lawrence's death a "horrible tragedy," then corrected himself, saying that "tragedy isn't the right word for it. It's just another example of reckless disregard for life. If you're using one of these things on the sidewalk, what do you expect?"

Williams said he will support new laws to control the use of "pocket bikes" and all-terrain vehicles in the city.

Council member Adrian M. Fenty (D-Ward 4) introduced emergency legislation earlier this year that would require operators of motorbikes to be 16 or older, register the vehicles and follow traffic laws.

At the site of the accident, residents are remembering Lawrence with balloons and teddy bears adorning a utility pole. Despite the tragedy, motorbikes are still being ridden recklessly, residents said.

Rosandra M. Hickson, 36, said young people in the neighborhood have been racing motorbikes in the same area since the accident. Just Wednesday afternoon, Hickson said, a young man was speeding through the courtyard at 3 p.m., a time when many children are walking home from school. Hickson said she called the police.

"He was going so fast," Hickson said. "He zoomed so fast. It doesn't make any sense. They already killed someone. But the only good thing was the police came fast."

Lawrence's mother, Althea Yelverton, who lives in Southeast, said yesterday that she's relieved that Powell turned himself in. She said she hopes he "pays for his crime."

"I thank God, thank God he's captured," Yelverton said. "I have a lot of support from my family."

Staff writer Lori Montgomery contributed to this report.

Christopher D. Powell is charged in boy's death.