A Northeast Washington man was charged with felony murder yesterday in the death of his girlfriend's 11-month-old son, who authorities said died of shaken baby syndrome. Police said it also appeared that the baby had been sexually abused.

Antonio M. Sears, 18, pleaded not guilty yesterday in D.C. Superior Court and was ordered held without bond. In charging documents, detectives said Sears told them that he shook the baby, Jabez J. Jasper, for about a minute on Dec. 13 because the child would not stop crying.

Jabez, who died Wednesday at Children's Hospital, also had serious infections on a knee and foot, where he apparently had been burned, the charging documents said. Other injuries were "consistent with sexual abuse," the documents stated.

The alleged shaking injuries took place at the apartment of Jabez's mother, in the Fort Dupont public housing complex in the 300 block of Ridge Road SE. According to the charging documents, the boy was eating french toast sticks -- "alive, healthy and breathing on his own" -- when his mother left him in Sears's care about 1:10 p.m.

About 2:45 p.m., firefighters were flagged down in the block and found the child on a tabletop in a neighbor's apartment, without a heartbeat. Sears initially said the baby choked while eating, the documents said.

Firefighters and ambulance workers managed to restore Jabez's heartbeat and took him to the hospital, according to one person on the scene. But the baby never regained consciousness. He was later found to have head trauma, including hemorrhaging of his brain, and other signs of shaken baby syndrome, authorities said.

The charging papers, prepared by detectives in the Special Victims Unit, said Sears told investigators that Jabez had cried incessantly after his mother left, and that he became frustrated and shook the child until Jabez "collapsed."

Sears, of the 200 block of 14th Street NE, was arrested in Temple Hills on Saturday night. He faces a preliminary hearing Jan. 6.

Jabez is at least the second child to have died of shaken baby syndrome in the District this year. In June, a Southeast Washington man was charged with felony murder in the death of his 6-week-old son.

Staff researcher Margaret Smith contributed to this report.