A body tentatively identified as that of Washington researcher Farlan Speer, who has been missing since he boarded a flight at Dulles International Airport in late 1975, was uncovered by the FBI late Wednesday in a shallow grave about 30 miles north of Oklahoma City.

Speer's body, which had three gunshot wounds in the head, was identified through dental records, the FBI said. Further records have been requested for a certain identification.

An FBI spokesman said that Speer had been buried in a two-foot-deep grave in a ravine and covered with rocks in the "rugged country" of Logan County, Okla. Agents found the site with the help of a confidential source and metal detectors, he said.

James Dee Francis Sheker, 46, who was arrested in California last week as a fugitive from a fraud charge in Prince William County, has been charged with the kidnaping of Speer. The FBI spokesman said, however, that Sheker has made no comment about Sheer's disappearance. No murder charges have been filed in the case.

Speer, who had a doctorate degree from Stanford and was a researcher at the National Academy of Sciences here, was last seen in November, 1975, as he boarded a plane at Dulles for a mysterious job interview in Oklahoma City.

Soon afterward, however, a man answering Sheker's description and using Speer's name, references and social security number began approaching oil and utility companies with investment opportunities. California authorities said Sheker had some of Speer's personal identification, including his college class ring, in his possession when he was arrested.