A 12-year-old Lanham boy was shot in the head and critically injured yesterday when a handgun which he and a friend were examining discharged unexpectedly, Prince George's County police reported.

Sylvester James Jackson, of the 9900 block of Goodluck Road, had been looking over a handgun which a 13-year-old friend from the same apartment building had brought to show him early yesterday morning, police said.

The boy was taken to Prince George's County General Hospital in Cheverly, where he was in critical condition yesterday, a hospital spokesman said.

"It was a freak accident," said Eula Jackson, Sylvester's mother, who was called at work by Sylverster's two brothers who told her of the shooting. "They were very good friends,' who played together often, she said.

Yesterday, as he was preparing to leave for junior high school, Sylvester's 13-year-old friend brought the handgun over to Sylvester's apartment in the Glenn Dale Woods complex. The two then began to examine the gun in Sylvester's bedroom, according to police.

"The gun was broken down into two parts," Eula Jackson said. "Neither of the boys knew there was a bullet in the gun." Police investigators said they were still trying to determine exactly how the gun could have discharged.

The boy's father, Edmund Harold said the boys were part of a group that play together in the apartment complex. "They were buddy-buddies. They skated together, played football together and went to school together."

No charges have been filed against the friend, whose name was not released by police.