A Lexington Park man faces murder charges after a 14-month-old child he was baby-sitting for suffered "blunt force trauma" to his head and later died, the St. Mary's County sheriff's office said yesterday.

Sheriff's deputies arrested Diosdado Bie David, 37, on Thursday night and charged him with first-degree murder, second-degree murder, child abuse and first-degree assault in the death Wednesday morning of James John Jones, the son of David's live-in girlfriend, Aubrey Jones, 19.

David, who is not the child's father, is being held without bond in the St. Mary's County Detention Center.

In addition to a blow to his head, the child had suffered an abdominal injury probably caused by a "tremendous strike or kick," and there were a number of bruises on his body, including one that was the "contour and size of a belt buckle," the D.C. medical examiner's office told St. Mary's authorities, according to charging documents. The autopsy was performed in the District because the boy died in a hospital there.

"We believe he committed this murder because he had sole care and custody of the child at the time of the injuries," St. Mary's sheriff's Lt. John Horne said. Ambulance personnel told doctors that David had been drinking, court records showed.

No one answered the door yesterday at the home David shared with Jones, his girlfriend of a few months. The tiny, white duplex is in the Lexington Manor development of run-down former military housing just outside the Patuxent River Naval Air Station in Lexington Park. Jones did not return telephone calls left on her answering machine.

Neighbors and friends of David and Jones expressed sorrow and shock over the child's death.

"He was a beautiful baby, a happy smiling little guy," said a teary-eyed neighbor, who said she baby-sat for the boy. She declined to give her name.

James John Jones spent most of the last evening of his life in the neighbor's care, eating a dinner of fruit and cereal before David picked him up about 10 p.m. Tuesday. The child had no injuries when David picked him up, authorities said yesterday, adding that David told them the boy was all right when they left the babysitter's home.

At 11:57 p.m. Tuesday, David called 911 and told the dispatcher that the child was having trouble breathing and was choking. Emergency personnel who came to the home revived the child twice after he stopped breathing, once on the way to St. Mary's Hospital in Leonardtown, once after they arrived. The child was later flown to Children's Hospital in Washington, where doctors said he was brain-dead on arrival. He died of cardiac arrest at 5 a.m. the next day.

Yesterday, authorities declined to elaborate on David's version of Tuesday evening's events. Horne said David has no prior criminal history or record of child abuse.

Florence Lindsay, a Lusby resident and grandmother of David's 6-year-old daughter from another relationship, said she can't believe David would have harmed the boy. "I've never seen him hurt my grandchildren. I've never even seen him spank one."