"Katherine departed from her family's residence on Plyers Mill Road in Kensington, Maryland on March 25, 1975 with her older sister Sheila between 11:00 a.m. and 12:00 p.m. The girls were walking to the Wheaton Plaza Shopping Center in Wheaton, Maryland, which was approximately one-half mile from their home and located on the corner of University Boulevard and Veirs Mills Road.

It was the first day of Easter vacation from school and Katherine and Sheila wanted to see the Easter exhibits at the mall, as well as have a pizza lunch at The Orange Bowl Restaurant. The girls' fifteen-year-old brother saw them inside restaurant eating pizza together at approximately 2:00 p.m. the day they vanished.

A friend stated that the girls were walking westward down Drumm Avenue near Devon Street between 2:30 and 3:30 p.m. This would have been one of the most direct routes to their home on Plyers Mill Road from the mall and was the final confirmed sighting of the sisters.

Their mother had instructed Sheila and Katherine to return to the residence by 4:00 p.m. When they did not arrive by 7:00 p.m. authorities were summoned and an extensive search was conducted. No evidence of the Lyon sisters' whereabouts could be located.

Several extortion-type phone calls were made to the Lyon family in the weeks following the girls' disappearances. The most serious call came from an unidentified male on April 4, 1975. The individual demanded that their father leave a briefcase with $10,000 inside an Annapolis, Maryland courthouse restroom.

The money was left as per the instructions, but was never claimed. The caller later maintained that police had surrounded the courthouse and he could not retrieve the ransom. Before the money would be offered to the man again, he was required to show evidence of the Lyon sisters in his custody. The caller said he would be in touch with the family, but never called back.

A witness in Manassas, Virginia reported seeing two girls resembling Sheila and Katherine in the rear of a beige 1968 Ford station wagon on April 7, 1975. The witness stated that the girls were observed bound and gagged in the vehicle at approximately 7:30 a.m. that day. The driver of the station wagon resembled the man seen questioning children at The Orange Bowl Restaurant the day the sisters vanished.

When the driver spotted the witness tailing him, he ran a red light and sped west on Route 234 towards Interstate 66 in Virginia. The station wagon had Maryland license plates with the possible combination "DMT-6**." The last two numbers are unknown due to the bending of the car's plate.

The known combination was issued in Cumberland, Hagerstown and Baltimore, Maryland at the time. A search for matching plate numbers failed to produce any information. This witness's report was at first treated as credible, but was later deemed "questionable" by police.

In 2014, authorities named Lloyd Lee Michael Welch Jr. and Richard Allen Welch, Sr. as the prime suspects in the sisters' cases. Lloyd, who is also known as Michael Lee Welch, is Richard's nephew. He was 18 years old in 1975. Photos of the men are posted with this case summary.

Lloyd has a record numerous criminal offenses, including sex offenses against young girls in South Carolina, Virginia and Delaware. Since 1997 he's been serving a 30-year sentence in a Delaware prison. He traveled throughout the United States from the 1970s to the 1990s and worked for a traveling carnival. He was at the Wheaton Plaza Shopping Center the day Katherine and Sheila went missing, and was observed watching them. Investigators believe Richard worked as a security guard at the area.

Lloyd told authorities he'd left the mall with Katherine and Sheila the day of their disappearances, and later saw his uncle sexually assaulting one of the them in the basement of his father's home in Hyattsville, Maryland. He told police his uncle and father dismembered the girls' bodies after they were killed, and the remains were taken to Taylor Mountain, 200 miles from their home, and burned. Richard apparently owned property on the mountain in the 1970s, and so did his sister.

A grand jury investigation into the children's disappearances began in 2014. Richard's wife, Patricia, testified, and authorities believe she lied on the stand; she was subsequently charged with perjury. In July 2015, a grand jury indicted Lloyd for two counts of first-degree felony murder in Sheila and Katherine's cases; the felony was abduction with intent to defile.

In September 2017, he pleaded guilty to both counts and admitted to the judge that he participated in the sisters' abduction, although he did not admit to any role in the killings. As part of the plea deal he also pleaded guilty to two unrelated sexual assaults on children committed in the 1990s; police learned of these crimes while investigating him in the Lyon sisters' case.

Lloyd was sentenced to 48 years in prison, and before he begins serving it he will have to finish serving a prison term in Delaware for the unrelated sexual assault of a ten-year-old child. Given his current age, it's unlikely he will ever be released.

Authorities stated there was a "conspiracy" in the Lyon sisters' presumed deaths and more people besides Lloyd were involved, but they stated the other suspects were either dead or didn't have enough evidence against them for charges. Lloyd's father died in 1998, and Richard has denied any involvement in Katherine and Sheila's cases.

Police found human DNA and what they suspect was human blood in the basement of Lloyd's father's former home in Hyattsville, but the sample was too degraded to make a match against anyone. Lloyd's attorneys stated their client has limited intellectual abilities and was taken advantage of by older adults when he helped abduct Katherine and Sheila.

Active searches for the Lyon sisters' bodies commenced in 2014, but nothing has been uncovered. Foul play is suspected in their cases due to the circumstances involved." (Information retrieved from CharleyProject.org)