BEDFORD, Va. (AP) _ Authorities have named a second person of interest in the 1975 disappearance of two young Maryland sisters. Montgomery County, Maryland, Deputy Police Chief Russ Hamill says it’s believed Richard Allen “Dick” Welch Sr. was a security guard in the Wheaton, Maryland, area where 10-year-old Katherine Lyon and 12-year-old Sheila Lyon disappeared after walking to a mall. A search has been ongoing on Taylor’s Mountain in the Thaxton area of Bedford County. At a news conference Thursday in Bedford, Hamill said it’s believed Richard Welch owned property there. He thinks “there’s a good chance” the girls are on the mountain. Hamill wouldn’t disclose Welch’s whereabouts. Police previously identified Welch’s nephew, Lloyd Welch, as a person of interest. He’s a child sex offender in a Delaware prison. A grand jury will convene Friday.