Barbara Bulter, a black woman who lives in College Park, had just finished watching the televised version of "Roots" last weekend when she looked out her window and saw flames shooting from a burning cross on her front lawn.

And another black Prince George's County woman, Gladstine Smith, of Oxon Hill, was fixing dinner earlier last month while her two daughters were doing homework when she was startled to see a three-foot burning cross in her back yard.

The two cross-burning incidents, and one other in Accokeek last month, are unrelated according to a Prince George's County Fire Department spokesman. Beyond that, the fire department, which is investigating the incidents, has no leads, the spokesman said.

The Prince George's County police, who have stepped up patrols in the areas where the incidents occured, have also looked into the matter. "It is bizarre," said one police spokeman who added, "This is something we take seriously and something we do not tolerate."

Speculating about the cause of the incidents, the county police spokeman said the incidents "were probably the work of kids with nothing better to do."

The executive director of the county human Relations Council, William A. Welch Sr. disagrees: "I doubt seriously that the incidents were pranks." Cross-burnings, he said have more "import" than pranks.

Another spokesman, Sylvester J. Vaughns, president of the Prince George's County Chapter of the NAACP said, "Police have taken the complaints very lightly.They have't made an effort to find the culprits. The problem is serious because cross-burnings carry the connotation of racial overtones."

The cross-burning victims take those incidents seriously too. "I am frightened. I can't sleep at night. Every little noise makes me jump up," said Mrs. Smith. She said she fears that the harrassment may contiune and that it might mean more vandalism, arson or something worse.

"It was the racial slurs that they yelled from the dark as they were hidden behind trees in our backyard that makes us know they were not just pranks," said Mrs. Smith.

Although Mrs. Smith does not believe the cross burning incident was prompted by the showing of "Roots" on television she said: "I wish they has seen "Roots" . . . If they had, they would have thought we had a mean streak in us and would have thought twice before burning a cross."