RICHMOND, Va. — A federal appeals court on Tuesday ruled that a judge consider DNA and other evidence that raise questions about the guilt of a former Army doctor convicted in the 1970 slayings of his pregnant wife and two daughters.

Jeffrey MacDonald, 66, is serving three life terms for the murders in a Fort Bragg home that spawned the book and television miniseries "Fatal Vision." He has always maintained that four drug-crazed hippies killed his family.

The 4th U.S. Circuit Court of Appeals heard arguments a year ago on whether to allow MacDonald to introduce new evidence, including DNA tests and sworn statements by two people who are now dead, which he says supports his claim of innocence.

In 1997, the appeals court ordered DNA testing in the case. Defense lawyers say a hair was found under the fingernail of one of MacDonald's daughters and contend that DNA helps prove the theory of intruders.

U.S. District Court judges have refused to review the DNA results on procedural grounds, but the appellate court ruled that the judges took an overly restrictive view of the evidence regarding both DNA and testimony by a former deputy U.S. marshal that the original prosecutor threatened a witness during MacDonald's 1979 trial.

"The opinion is being studied by attorneys for the government both in our office and in Washington to decide how best to proceed," U.S. Attorney George Holding said in a statement. "Our office remains committed to defending the unanimous guilty verdict reached by the trial jury after a seven-week trial in 1979, which has withstood numerous previous legal challenges by MacDonald.”