BEDFORD, VA., JUNE 13 -- Elizabeth Haysom testified today that she and Jens Soering plotted her parents' murders during a weekend trip to Washington and that he drove to their home and stabbed them to death while she created alibis. Soering's defense maintains that Haysom committed the 1985 slayings.

Haysom, who is serving a 90-year prison sentence for being an accessory to her parents' murders, said she found out that her boyfriend had carried out the plan when he picked her up in a rental car outside a movie theater, their designated meeting place, and opened the passenger-side door to let her in.

"He had a sheet . . . draped over him and it had a great deal of blood on it," Haysom said. "I said, 'Oh my God, you attacked them.' He said, 'That's right.' He told me to shut up and close the door. He said he had killed my parents."

Later in her testimony, which will continue Thursday, Haysom said, "I believe he killed my parents out of love for me."

Haysom, 26, is the prosecution's key witness at Soering's trial on charges of murdering her parents, Derek and Nancy Haysom, at their Bedford County home in March 1985. She and Soering, 23, the son of a West German diplomat, were honor students at the University of Virginia and were involved in what psychiatrists described as an obsessive, mutually dependent love affair in 1985.

Soering's defense attorney, Richard Neaton, maintained in opening arguments last week that it was Haysom who drove to Bedford County, killed her parents and then persuaded Soering to "switch roles" and falsely confess to the slayings because he would be protected in part by his father's position.