(Reuters) - Authorities said bad weather on Friday cut short the work of investigators in rural Virginia probing the abduction and murder of two young sisters who disappeared while going to see an Easter exhibit at a Maryland shopping mall nearly 40 years ago.
For a week, detectives have been looking for evidence and gathering information around Taylor Mountain, east of Roanoke, in connection with a person of interest in the case who was named earlier this year.
Authorities said Friday's hiatus would let them analyze further the new information, which police have said may indicate that the man, Lloyd Lee Welch, and his relatives are linked to the disappearance of the girls and their death.
The Bedford County Sheriff's Office, which is working with the Virginia State Police and the police department of Montgomery County, Maryland, added on Friday that prosecutors are evaluating the results of the investigation and potential charges.
The investigators "have been obtaining and assessing a large quantity of information and evidence that establishes the involvement of the individuals responsible for the abduction and murder of Sheila and Katherine Lyon in 1975," the sheriff's office said in a statement.
"Authorities remain confident that justice will be obtained in this case," it added.
Welch, a 57-year-old former drifter and carnival ride operator who worked in about a dozen states from the 1970s through the 1990s, has been imprisoned in Delaware since 1997 on child sex-related convictions.
Police say they believe he was at the Wheaton Plaza mall, in a Maryland suburb of Washington, on the day in March 1975 when Katherine and Sheila Lyon, aged 10 and 12, vanished.
But they have declined to discuss specifics of what prompted their interest in Welch, who has convictions for raping young girls in Virginia, Delaware and South Carolina.
The sisters, daughters of a local radio personality, were last seen talking to a man at the mall who had a tape recorder in a briefcase. Their disappearance shocked the community and triggered extensive searches by police and the National Guard.
When police and the FBI announced in February that Welch was a person of interest in the case, investigators also said they were looking for information about Helen Craver, his girlfriend and co-worker at a carnival company who has since died, and about security guards who were working that day.
(Reporting by Daniel Wallis in Denver; Editing by Mohammad Zargham)