An ex-Marine accused of writing a "recipe for murder" on a computer and killing his wife was convicted of murder Friday by a federal jury despite the fact that her body was never found.

Robert Russell, 33, showed no emotion as he stood with his two defense lawyers while the first-degree murder verdict was announced, but some of his relatives cried.Prosecutors said Russell killed his wife Shirley at her Quantico Marine Base quarters and dumped her body in an abandoned coal mine in Pennsylvania. But defense witnesses testified they saw her alive after she was reported missing March 4, 1989.

The body of the woman, a Marine captain, was never found. The government based its case largely on circumstantial evidence, including a document found in his computer.

Prosecutors called the computer file a 26-step "recipe for murder," but Russell said it only contained notes for a mystery novel he wanted to write.

The jury of four women and eight men deliberated about 15 hours over three days. The panel considered testimony from 62 witnesses and more than 50 exhibits.

Two jurors said afterward the deliberations were troublesome.

U.S. District Judge James Cacheris set sentencing for Aug. 2.

The jury began deliberations Wednesday. FBI agents armed with a warrant searched Russell's home on Thursday. One of his attorneys Friday asked for a dismissal because of the search, but Cacheris denied the motion.

Defense lawyer Drew Hutcheson told the judge five FBI agents searched the defendant's home at Mahanoy City, Pa., for 90 minutes looking for a box that may have contained some rings. He pleaded with the judge that "Bob is here fighting for his life."