On a spring morning in 1975, Sheila Lyon, 12, and her sister Katherine, 10, walked to a shopping mall in Wheaton for lunch and some window shopping. Their brother saw them there, eating pizza.

But the girls never came home.

A massive search ensued. Police, tracking dogs, National Guard members, motorists on CB radios. Detectives chased one lead after another, but all were dead ends.

Now, nearly 40 years later, Montgomery County police may be close to finding out what happened to the sisters. On Tuesday, they announced that a 57-year-old convicted sex offender named Lloyd Lee Welch is a “person of interest” in the case and asked that anyone who knows him contact them.

Welch was a drifter from the District who walked along railroad tracks and hitchhiked to get around. For a time, he operated rides for a traveling carnival. And on March 25, 1975, police said, he visited the Wheaton Plaza shopping mall, where he seemed to pay special attention to the Lyon sisters.

Mugshot of Lloyd Welch from 1977, when he was arrested in a residential burglary near Wheaton Plaza. (Montgomery County police)

“We need everyone who may know something to come forward,” Steve Vogt, special agent in charge of the FBI in Maryland, said Tuesday. “It might be enough to put the pieces of this puzzle together.”

Montgomery Police Chief J. Thomas Manger stressed that detectives don’t have evidence to file charges against Welch but are continuing to try to learn as much about him as they can.

“This case shocked our community in 1975 and has never been forgotten,” Manger said.

Longtime residents certainly feel that way. To them, the Lyon sisters are part of Montgomery’s history, their disappearance a seminal event that signaled that it was no longer safe for girls to walk alone — or that it never really had been. “It kind of traumatized the area,” said Steve Murray, who has a Facebook page named “Wheaton Plaza,” on which people post memories of the now renovated and renamed mall, sometimes still mourning the loss of the girls. “This was such a sad time and it changed the way a lot of us lived,” Sharon McDaniel, who lived in Kensington, wrote there Tuesday.

In a statement provided by police, the Lyon family asked for privacy and said they would be “grateful for any information the public can provide to help bring this story to its conclusion.”

“March 25th will mark 39 years since Kate and Sheila were taken from our family,” they said. “Throughout these years our hopes for a resolution of this mystery have been sustained by the support and efforts of countless members of law enforcement, the news media, and the community. The fact that so many people still care about this case means a great deal to us.”

Police knew about Welch early in the investigation, authorities said, but it’s not clear whether they ever suspected that he could be involved. Back then, he was 18 years old and was known to stay in homeless shelters and hotels. He had a serious girlfriend, police said, who also worked with the carnival. It would be decades before his convictions for sex crimes in other states.

Late last year, Montgomery detectives looking through the case files began to take a new look at Welch. “He jumped out at us in the past couple of months,” said Assistant Montgomery Police Chief Russ Hamill.

Old case file documents show that a young girl who was with the Lyon sisters that afternoon had described a man who followed the three of them that day. Police developed a sketch partly based on that description, they said. It resembles a mug shot taken of Welch a few years later — in 1977 — when he was arrested in a burglary case in Montgomery.

Welch went on to assault girls in South Carolina and Delaware, where he is in prison, police said. The details of the Delaware case are not clear, but court papers show that he pleaded guilty in 1998 to several sex offenses. Officials said he is due to be set free in 2027 but has asked for early release. The Board of Pardons has scheduled a hearing for July.

Welch’s niece, Debbie Roe, 38, of Dover, Del., said she is the only member of the family who is in regular contact with him. She said she has written letters on and off to him for the past 13 years during his incarceration. She described him as “sweet” and said he is excited when she visits him in prison.

She said that Welch has denied involvement in the disappearance of the Lyon girls but told her that he was at Wheaton Plaza that day.

“The only thing he said he did was walk around the mall,” Roe said. “I think they need to look elsewhere. He doesn’t know where the girls are.”

Darlene Hawn, 57, Welch’s half sister, said news of his possible involvement was a surprise. “I don’t know what to say,” said Hawn, also of Dover. “It’s just a shock.”

Family members said that Welch had a difficult childhood. They said his father was driving drunk one night and crashed a car, killing his wife. Welch was a passenger in the vehicle, relatives said. After that, Welch was put in foster care, but they added that he briefly returned to live with his father and stepmother at their home in Hyattsville when he was 11 or 12. They also said he had brushes with the law. “He never stayed home,” Hawn said. “He was always going places and getting into trouble.”

Dolores Askins of Silver Spring said her sister, Helen Craver, dated Welch for about 10 years starting in the 1970s. During that time, Askins said, the couple worked for a variety of carnivals, setting up rides and tending the grounds. They lived on the road and had no permanent home. Askins said that they had four children together but that authorities eventually removed them because the couple were unable to provide for them.

“Nobody was happy that she took up with Lloyd,” Askins said. “Everybody was happy when she left him simply because of what she had been through.”

Askins said that Craver eventually remarried but never got her children back. She said that Craver died several years ago.

Police said that Welch — who also went by the name Michael Lee Welch — has traveled from state to state, and they released a timeline of places he has lived in or visited. During a 20-year stretch, he has been in at least six states — from Sioux City, Iowa, to Los Angeles to Union County, S.C. He also has worked as a landscaper.

Police said detectives are trying to find security guards who worked at Wheaton Plaza in 1975 and might have had some contact with Welch, particularly one who held the rank of captain. They want to hear from anyone who knows him or knew his girlfriend.

Police said they still don’t know what happened to the Lyon sisters but will keep looking for answers.

“The family deserves justice,” Manger said.

Lynh Bui, Jennifer Jenkins, John Kelly, Patrick Svitek and Matt Zapotosky contributed to this report.

FBI timeline of Welch’s travels

How contact law enforcement about the case: Call 1-800-CALL-FBI or visit tips.fbi.gov

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