BEDFORD, Va.>> It was an innocent time in a safe place, where parents didn’t think twice about letting their kids walk to the local shopping mall. All that changed the day the Lyon sisters disappeared.

A sense of security was shattered in the spring of 1975, when two young sisters from the Maryland suburbs of Washington went to the mall to have pizza with friends, but never made it home.

Today, one of the region’s most painful and enduring mysteries came to an end when a 60-year-old convicted sex offender pleaded guilty to felony murder in the deaths of 10-year-old Katherine and 12-year-old Sheila Lyon.

The case haunted the region for decades.

“That fear lingered for years and years, and it was just the kind of thing that nobody will ever forget,” said retired Sgt. Harry Geehreng, who searched for the girls at the shopping center and in nearby woods in the days after they vanished.

Parents were afraid to let their children go outside. Walks to the mall and other unsupervised activities also came to an end, said Teresa Brookland, a former schoolmate of Katherine Lyon.

“Our parents were very protective. They were quite rattled by this,” Brookland said.

The crime went unsolved for decades, and the girls’ bodies were never found. Finally, in 2013, cold case detectives in Montgomery County, Maryland, honed in on Lloyd Lee Welch Jr., who fit the description of a man a friend of the girls told police she saw staring at the sisters the day they disappeared.

Welch was sentenced to 48 years in prison today after pleading guilty to two counts of first-degree felony murder. He admitted participating in the abduction of the girls, but continues to insist he did not participate in any sexual assault of the girls or in their killings, said his attorney, Tony Anderson.

The 48-year sentence is part of a plea agreement that also calls for him to receive a 12-year concurrent prison term for two unrelated sexual assaults in northern Virginia.

The Lyon sisters disappeared on March 25, 1975, after walking from their home in Kensington, Maryland, to the shopping center.

Welch was charged in the girls’ killings in 2015 after members of his extended family said they saw him carrying two large duffel bags on property the family owned on Taylor’s Mountain in Bedford County, Virginia.

During Welch’s plea hearing in Bedford Circuit Court today, Commonwealth’s Attorney Wes Nance said witnesses told authorities Welch put a green duffel bag in a large fire burning on the mountain. Nance said other witnesses recalled that the fire burned for days and had “the stench of death.”

Welch, now 60, did not speak during the hearing, except when asked to enter his plea. He did not address the Lyon family when asked by Judge James Updike Jr. if he had anything he wanted to say.

“It’s our hope that with this agreement … will in some way add some closure in a meaningful, meaningful way to the Lyon family and Mr. Welch,” Anderson said.

Nance said Welch repeatedly changed his account of who else was involved in the crime during 13 interviews with police, beginning in 2013. “His credibility is open for questioning,” he said.

Authorities had named Welch’s uncle as a person of interest in the case, but Nance said they were never able to develop enough evidence to charge him or anyone else.

Nance said Welch’s admission that he participated in the kidnapping fits the definition of felony murder — a killing that occurs during the commission or attempted commission of a felony.

Welch had faced the possibility of the death penalty. Nance said prosecutors decided against pursuing a death sentence based on changes in the law that could have prompted years of appeals and the Lyon family’s wish to bring the case to a close.

The girls’ parents, John and Mary Lyon, and her two brothers, thanked Montgomery County police for sticking with the investigation.

“We just want to say, simply, ‘thank you,’ and it’s been a long, long time, and we’re tired, and we just want to go home,” John Lyon said.

Welch is now serving a prison sentence in Delaware for sexually assaulting a 10-year-old girl. Once he completes that sentence in 2026, he will begin serving his sentence in Virginia.

Nance said because the crime was committed in 1975, before truth-in-sentencing laws were passed, Welch could become eligible for parole when he reaches his early- or mid-80s. But he called the chances of Welch actually getting paroled “very slim or none.”