The nude body of a 13-year-old Landover girl who had been missing since late Friday night was found late yesterday atternoon concealed in some bushes in her back yard. Prince George's County police reported. They said she had been stabved to death.

Cynthia Gray, of 7202 East Inwood St. was found by police who had been searching for her since her father Thomas Gray, reported her missing early Saturday morning.

Gray, a widower, had come home early Saturday morning and was told by his son, Thomas Jr., 12, that Cynthia was not in the house.

"At first I thought she had gone across the s treet to dart Drug or to visit some friends. But then when she didn't come home and none of her friends knew where she was, I started wondering," Gray said yesterday.

"I checked the kitchen door and it looked like it had been forced, broken into. Then I found her housecoat in the kitchen, too. That's when I called the police."

Police came to the house Saturday morning, Gray said, and began investigating the possibility that Cynthia had run away or was a friend's house by choice.

"When I checked around, none of her clothes were gone at all and her shoes were in the bedroom," he said. "I begun to think she walked in on a burglary or something."

Police apparently began to believe the same thing by yesterday afternoon. Seat Pleasant Detective James King, assigned to the case, said he did a complete check of friends and the neighborhood and searched the area.

"We're still hoping she's with a friend or run away, " King said about two hours before the body was found at 5 p.m. "But we've checked with all her friends and canvassed the entire neighborhood."

King agreed with Gray that the house appaently had been broken into although nothing had been taken. He would not comment on what he though happened but police sources, like Gray, speculate that Cynthia Gray may have walked into the kitchen while a burglary was in progress.

Cynthia was found after police stepped up their search of the neighborhood with darkness closing in. She had been stabbed several times in the body, and it appeared she had been concealed on purpose, in some bushes, police said.

According to police, the bushes where the body was found are loeated directly behind the house, a few feet away from Kilmer Street, which runs behind the house.

Cynthia was a seventh-grade student at Charles Carroll Junior High School, according to her father. The Grays moved to Landover from Calvet County about 18 months ago shortly after Mrs. Gray died. Mr. Gray works as a cabinet maker for the Smith-sonian Institution.

Gray said that he had been visiting his fiancee, Willy Clark, in Northwest Washington on Friday night. Arriving home Saturday morning he was informed by his son Thomas Jr. that Cynthia, whom the boy had seen in the house just before he went to bed at 10 p.m., was missing.

Police last night were questioning Gray and his son and were trying to pinpoint the time of the apparent break-in. An authopsy to determine the cause of death, the approximate time of death and whether the girl was molested is scheduled today at the state medical examiner's office in Baltimore.