BEDFORD COUNTY, Va. (WUSA9) -- Detectives from the Montgomery County Police Department have not only expanded the search area for clues relating to a 1975 cold case, they've also expanded the number of people they believe were involved.
Montgomery County police along with Virginia authorities are searching a rural part of Virginia for evidence in the 1975 disappearance of the Lyon sisters, police confirmed Tuesday.
Sheila Lyon, 12, and her sister Katherine, 10, walked to the nearby Wheaton Plaza shopping center from their Kensington home one afternoon in 1975. They were never heard from again.
Thirty-nine years later, in February of 2014, Montgomery County police and the FBI named Lloyd Lee Welch Junior a person of interest in the Lyon sisters case. Witnesses placed him at Wheaton Plaza and said he was paying extra close attention to the girls.
Authorities know who is responsible for the abduction and murder of the Lyon sisters, and said "it includes Lloyd Welch and family family members," Montgomery County Police Captain Darren Francke said .
Francke would not specify on which family members and how many police believe were involved.
"I'd rather not say right now, they know who they are," said Francke, adding that the relatives who police are interested in are still alive.
Lloyd Welch has been in a Delaware prison since 1997, when he was convicted of sexually assaulting a 10-year-old girl in the 90s.
During their investigation, detectives determined that Welch had connections to Bedford County, Virginia, police said. Detectives are searching property in the Taylor Mountain area, in between Roanoke and Lynchburg, for any evidence that may link Welch to the disappearance of the sisters.
Included in the search area is property that once belonged to Welch's relatives.
"This is a large area and we want to make sure we are thorough we are grabbing every piece of evidence off that mountain," said Captain Francke.
The detectives are working with the Bedford County Sheriff's Office and the Virginia State Police while they search the area.
Detectives from the Montgomery County Police Department have been in Bedford County since last week, police said.
WATCH most recent press conference on the search of the Lyon sister:
Read the original story on Welch as a person of interest HERE: http://on.wusa9.com/1fcrjLX