Prince George's County police, acknowledging that they have no suspect in the stabbing death of 13-year-old Cynthia Gray, continued yesterday to investigate the possibility that she was killed after surprising a burglar who broke in to her Landover home through the kitchen door.

Cynthia's nude body was found in a clump of bushes behind her home at 7202 E. Inwood St. at about 5 p.m. Sunday. She had disappeared between 10 p.m. Friday, the last time her 12-year-old brother Thomas Gray Jr., saw her, and 9 a.m. Saturday when her father, Thomas, started looking for her.

An autopsy performed yesterday confirmed that Cynthia had been stabbed numerous times in the chest. Dr. Marguerita Korell of the state Medical Examiner's Office said it will be several days before tests can determine whether Cynthia had been sexually molested.

Police said Gray, a cabinetmaker at the Smithsonian Institution, found that his daughter was missing when he returned home Saturday after spending Friday night with his fiance in Northwest Washington. Gray then discovered his daughter's torn bathrobe in the kitchen and noticed that the door appeared to have been broken open, although nothing was missing, police said.

Neighbors said yesterday they had heard no disturbance at the Gray home Friday night and described the family as closely knit. Gray "being widowed seemed to pull them together." one friend said. "He always called Cynthia, 'My little girl.'"

A cousin, Geraldine Baylor, said "it wasn't unusual for Cynthia and Buster Thomas Jr. to stay here at their homealone. They took care of each other."