D.C. police were seeking a 30-year-old man last night on charges that he struck and killed a 5-year-old boy last week while riding a motorbike through the courtyard of a Southeast Washington apartment complex, authorities said.

Christopher D. Powell of the 2300 block of Green Street SE was charged with second-degree murder in the arrest warrant, D.C. police said.

Powell is accused of riding the motorbike that struck and critically injured two boys about 4:30 p.m. Oct. 28 on a paved walkway at the complex in the 2700 block of Langston Place SE.

Lawrence Yelverton of the 2300 block of Hartford Street SE died of his injuries the next day at Children's Hospital.

Charles Fenwick, 4, was critically injured. His condition could not be determined yesterday.

The two boys and several other youths were walking home with an adult caregiver from a nearby day-care center when the accident occurred, police said.

Investigators said assistance from the public helped them to obtain the warrant. Authorities were concentrating their search for Powell in Southeast and areas of Maryland, police said.

Police alleged that Powell had been driving a mini-motorbike throughout the Langston Place neighborhood for hours before the accident. After the motorcycle struck the children, witnesses told police that Powell walked away from the scene, authorities said.

The motorbike was found in the entryway to an apartment about 250 feet from the path, police said. Investigators are not sure whether Powell or someone else moved the bike there.

Police had been seeking Powell since late last week, investigators said. They said a man who identified himself as Powell called investigators Saturday and said he had been riding the motorbike. He told investigators he was driving fast and could not stop before striking the children, police said.

Police urged anyone who witnessed the incident to call them at 202-727-9099.