A Prince Georges County policeman yesterday shot and killed an unarmed 18-year-old Palmer Park man who police said was climbing out of the rear window of a restaurant he was burglarizing.

Officer Lester J. Bethel ordered the man to freeze as he saw him allegedly emerging from the Palmer Restaurant in Landover. When he moved his right shoulder, police said, the officer fired two shotgun blasts and the youth fell back inside the restaurant dead.

Abraham Dickens IV, 18, of 7737 Burnside Rd., was pronounced dead at the scene of the shooting, police said. His parents said the youth was most recently employed as a maintenance man at a District office-apartment complex.

Police said the officer had identified himself and shouted to the youth not to move. After firing the first round, police said Bethel dropped to his knee and fired a second.

The window where the youth appeared is three or four feet off the snow-covered ground. From the rear of the building the window faces the rear parking lot. It is adjacent to a drive-in window of a liquor store attached to the restaurant. Inside the bathroom where Dickens was found, there is a four foot drop to the floor from the window.

Police said the youth was struck in the left side by one or both of the shotgun blasts.

Yesterday's shooting of a black by a white policeman comes amidst a police and grand jury investigation into the fatal Christmas Eve shooting of an unarmed 32-year-old black man and alleged shoplifted by another white county officer who was pursuing him. The officer has been charged administratively with violations of county police firearms regulations.

The county also has a history of controversy over black-white police incidents and over the racial policies of overwhelmingly white county police department.

County firearms regulations do permits an officer to shoot in order to apprehend someone who has committed a "violent type of crime," a category that "may include" burglary or breaking and entering.

The incident began at approximately 5:30 a.m. according to county police, who said Bethel and another rant by a silent alarm signalling a break-in.

Police said the unidentified officer talked to a witness in front of the restaurant while Bethel went to the rear to look around.

The youth, who allegedly entered the building through a rear window was exiting through a rear bathroom window when Bethel appeared, police said.

The manager of the restaurant said he could not determine whether anything was missing yesterday.

"I just want to know what happened," said Abraham Dickens III, the youth's father. "I can't believe it. I still don't know what happened to my son. I was too shocked to understand when police told me."

The dead 18-year-old, who was called "Cotton" by his friends in the neighborhood where he lived, had been convicted previously for shoplifting, according to his parents.

The officer was routinely placed on administrative leave, pending the outcome of an investigation into the shooting.