On March 25, 1975, Sheila Lyon, 12, and her younger sister Katherine, 10, left their family home in Kensington, Maryland, for what was supposed to be an ordinary afternoon at a nearby shopping center.
They were on Easter vacation. Their destination was Wheaton Plaza, where they planned to meet friends, look at Easter displays and have lunch.
Their mother expected them home by 4 p.m.
They never returned.
What followed became one of the Washington region’s most enduring missing-person investigations — a case that would remain unresolved for more than four decades, survive thousands of tips, repeated searches and changing investigative theories, and eventually depend on a clue that had been sitting inside the original police files for years.
In 2017, Lloyd Lee Welch Jr. pleaded guilty to two counts of first-degree felony murder in connection with the deaths of the sisters.
But even after the conviction, one of
