WASHINGTON (Reuters) - Police have identified a "person of interest" in the 1975 disappearance of two Maryland sisters, one of the highest-profile missing-persons cases in the Washington, D.C. area, authorities said on Monday.
Police in Montgomery County, Maryland, said they would announce a major development on Tuesday in the March 1975 disappearance of Sheila Lyon, 12, and her sister Katherine, 10, at the Wheaton Plaza mall in suburban Washington.
"Detectives have identified a person of interest who was at Wheaton Plaza on the day the girls disappeared," the Montgomery County Police Department said in a statement.
The man is a convicted child sex offender, now imprisoned, and had traveled widely around the United States, it said. The statement did not name the man.
A news conference with police and the Federal Bureau of Investigation is scheduled for Tuesday.
The girls - daughters of Washington radio personality, John Lyon - went to the mall on March 25, 1975, to see the Easter exhibits. They were last seen walking near the mall in the direction of their home.
Extensive searches were carried out, including by National Guard troops, but no trace of either of the two sisters was ever found.
A witness told police he saw the Lyon girls talking to a man at the mall who had a tape recorder inside a briefcase.
The police statement said investigators were requesting help from the public in gathering information about the person of interest.
(Reporting by Ian Simpson, editing by G Crosse)