with a washcloth forced down her throat. Her body was loaded into the trunk of a rental car and, with her four children in the back seat, Frank and Diane drove to the farmhouse in the small town of Farnham. There, Martha's body, wrapped in her bedclothes, was buried in a shallow grave. NATIONWIDE SEARCH The couple and their infant fled a month later, leaving the four boys alone in a motel. A nationwide search found Frank and Diane in Boise, Idaho, on July 11, 1975. Frank would soon plead guilty to murder in Delaware County Court and be sentenced to life in prison. He is at the State Correctional Institution in Dallas. Diane Metzger insists she didn't go into the home until the body was in the trunk of the car, and did not help plan the murder. Prosecutors contend she helped remove the body and helped plan the killing. Preate is convinced by the prosecution's case, and said Metzger must apologize for her role before she gets his vote. "If you deny you've been a participant in a murder, how can you ever be rehabilitated?" Preate asked. But on Friday, Metzger said, "They can contend anything they want to. . . . I wasn't in the house when Marty was killed." Metzger was angry, eager to speak sometimes and reluctant to talk at other moments. "I have a real problem talking about this because it still brings back the nightmare and brings back the horrors. No one can bring back Marty, but I don't know what's to be gained by . . . reliving it . . . this was supposed to be a clemency hearing, not a retrial." She said the publicity hurts her parents, her son and "Marty's sons, wherever they are." Since her sentencing in 1977, Metzger has achieved more scholastically behind bars than many people do in a lifetime of freedom. "One of the more extraordinary applicants that I've interviewed," says J. Harvey Bell, her advocate before the Board of Pardons. Having earned one college degree, Metzger is now working toward a master's in public administration. SCHOLASTIC AWARD She has a paralegal certification from Penn State. She was named ''Outstanding Adult Student in Higher Education" in 1989 by the Pennsylvania Association of Adult Continuing Education. She earned an associate's degree in business administration in 1980 and completed an electrician's training apprenticeship in 1986. She is a member of MENSA, the organization for people with high IQs. She has earned eight prison education certificates in subjects ranging from sign language to word processing to technical photography. Then, there's her poetry. In her seven-page application she lists 19 writing awards - mostly for poetry - and mostly in contests for prisoners. In at least one instance, however, Metzger overstated her accomplishments. She claims to be the author of a song, "Sleep Now, My Baby," published in