EXCLUSIVE: Justice may have been served in the brutal slaying of the Lyon sisters, but for Sgt. Chris Homrock, there are no winners here.

The gory case is the subject of a new true-crime documentary on Investigation Discovery (ID) airing Saturday titled “Who Killed the Lyon Sisters?” which explores how the murder mystery was solved over four decades later.

Homrock, who has been with the Montgomery County Police Department in Maryland for 26 years and currently serves as a detective sergeant, came forward to share his story in the special. He was the supervisor of the Lyon sisters’ task force.

The Lyon sisters are the subjects of a new true-crime documentary on Investigation Discovery (ID).

The Lyon sisters are the subjects of a new true-crime documentary on Investigation Discovery (ID). (ID)

“Even though we got a conviction, we still don’t really consider this a success,” Homrock told Fox News. “There are some open questions that we never really got the answers for. We never really found the remains, which we wanted to bring home for the families. We can only really speculate what happened to those girls on the last day they were alive.”

DOCUMENTARY: MINNESOTA MAN MURDERED BY SIBLINGS FELT THREATENED BEFORE GRISLY END

It was March 25, 1975, when 10-year-old Katherine and 12-year-old Sheila Lyon, daughters of well-known Washington radio personality John Lyon, walked to a shopping mall near their home in Kensington, Maryland. The girls vanished and their bodies were never found.

In the documentary, Lloyd Lee Welch Jr., a convicted sex offender, claimed to police decades later that he helped abduct the girls and then delivered them to his father Lloyd Welch Sr. and uncle Richard Allen Welch Sr. 

Sgt. Chris Homrock has been with the Montgomery County Police Department in Maryland for 26 years.

Sgt. Chris Homrock has been with the Montgomery County Police Department in Maryland for 26 years. (ID)

Welch, who was 18 at the time of the disappearance, alleged that he witnessed the men rape at least one of the girls and dismember the other in the dungeon-like basement of the patriarch’s home, Hyattsville Life reported. Homrock pointed out that despite the allegations, there wasn't sufficient evidence to support any of Welch's claims.

However, Welch’s cousins Connie Akers and Henry Parker would later testify that after the disappearance, Welch unexpectedly showed up at their property on the remote Taylors Mountain in west-central Virginia with bloody clothing. At the time, Welch said he was carrying ground beef that had gone bad. Years later, neighbors recalled witnessing a bonfire and its distinct pungent smell. 

CALIFORNIA MURDER-FOR-HIRE PLOT LED BY RUTHLESS DEBT COLLECTOR EXPLORED IN NEW DOC: 'HE WAS PRETTY EVIL'

Despite Welch being a person of interest who had cousins, an aunt, uncle and relatives living on the rural mountain, the mystery remained unsolved.

Lloyd Lee Welch Mugshot on a desk at the Montgomery County Police Dept.

Lloyd Lee Welch Mugshot on a desk at the Montgomery County Police Dept. (ID)

“Lack of evidence was a large part of it,” Homrock explained. “There were a number of suspects in the case file, and the case was about 20 boxes of reports, files and information. There were at least three really good suspects who were documented child predators, who were in the area at the time… Each of these suspects involves intense investigation, traveling across the country and interviewing victims, family members, people who knew these guys… But we persisted.”

For decades, the mountain had a reputation as a rough-and-tumble place where people watched out for each other and were reluctant to deal with outsiders. 

It wouldn’t be until 2013, when detectives from the cold case unit in Montgomery County, Maryland, showed up did people on Taylors Mountain began talking about the cold case. Welch, who was long imprisoned for sexually assaulting another girl, was scrutinized based on a review of evidence in the case file.

CHRIS WATTS’ FINAL TEXTS TO PREGNANT WIFE SHANANN WATTS BEFORE GRISLY MURDERS REVEALED IN NETFLIX DOC

Lyon sisters case file - one of many.

Lyon sisters case file - one of many. (ID)

It was then when Welch’s cousins told police they remembered Welch’s visit - and how he carried a duffle bag carrying bloody clothing, which he claimed was used to carry meat. Another told them Welch had two army-style duffel bags with reddish-brown stains on them, and that he helped Welch put the bags into a fire.

Other people who lived on the mountain came forward to investigators and described a fire that burned for days with “the stench of death.” 

“One person said it best, ‘What happens on the mountain, stays on the mountain,'" said Homrock. “The bonfire, the smell of burning flesh and hair was never reported to the police. It wouldn’t be until our [cold case team] began further investigating, interviewing people that they began to speak... But believe it or not, there are good people who wanted to help solve this case."

Front Door of the Welch family property on Taylors Mountain, Virginia.

Front Door of the Welch family property on Taylors Mountain, Virginia. (ID)

“Welch was described as the black sheep of the family,” he shared. “The kids were told to stay away from him. The adults pushed him away. His own father and uncles pushed him away. He was bad news. And yet none of them ever called the police. But the kids, who are now adults, told us that the older Welch relatives told them to steer clear of Lloyd and not to associate with him.”

CONNECTICUT MOM RECALLS LOSING TWO DAUGHTERS, GRANDDAUGHTER IN HEARTBREAKING DOC

In 2014, authorities began digging on the mountain in hopes of recovering the girls’ remains. They did discover a tooth, according to documents filed in court, but authorities have never said if they were able to match it to the girls’ dental records. 

Homrock described Welch as a “psychopath” who abducted the girls during a moment of opportunity. Welch also came from a dysfunctional household and claimed he was sexually abused as a child by relatives.

Ted Welch, a relative of Lloyd Lee Welch, participated in the ID special.

Ted Welch, a relative of Lloyd Lee Welch, participated in the ID special. (ID)

“He is where he needs to be,” Homrock explained. “He’s very cunning. He would interview the detectives as much as we were interviewing him. He was trying to see how much information we had learned about him. There were a lot of cat-and-mouse games with him. He was very tough to pin down in terms of getting anything from him.”

“One of the witnesses that we found who was at the mall that day -- she was a teenager herself back then -- remembered Lloyd just completely focused on the Lyon sisters and following them around. It gave her the creeps," Homrock reflected. "She immediately gave information to police and a sketch was made."

NICOLE BROWN SIMPSON’S PAL RECALLS HEARING HER HEARTBREAKING DIARY ENTRIES IN DOC: ‘WE WERE IN TEARS'

However, the sketch, which proved to be incredibly accurate, was not disseminated widely and it seemed that it may not have been circulated well within the police department, Salon reported.  According to the outlet, Welch later confirmed to police that he was the man in the sketch.

Katherine and Sheila Lyon's childhood home, present day.

Katherine and Sheila Lyon's childhood home, present day. (ID)

In 2017, Welch pleaded guilty to murdering the Lyon sisters. He was sentenced to 48 years in prison and will also finish serving another 10 years for an unrelated sexual assault of a 10-year-old girl, Hyattsville Life reported. He will not be eligible for parole, but Homrock is confident Welch will spend the rest of his life behind bars.

Homrock also said the parents of the Lyon sisters have “become family” for the investigators.

“The family never stopped looking for answers,” he said. “And it was our duty to bring them justice. Even though the case has concluded and we don’t have all the answers we’re still in contact with the family… And Lloyd will never get out. I think anybody who ever spends time with Lloyd will quickly realize that if he’s ever free, it’s just a matter of time before he would do this again.”

'BUTCHER BAKER' PROSECUTOR SAYS ROBERT HANSEN WAS 'A SMALL GUY' WHO QUICKLY TRANSFORMED INTO 'A MONSTER': DOC

Mother Mary Lyons is pictured getting a hug after Lloyd Lee Welch Jr. was indicted on first-degree murder charges.

Mother Mary Lyons is pictured getting a hug after Lloyd Lee Welch Jr. was indicted on first-degree murder charges. (Photo by Sarah L. Voisin/The Washington Post via Getty Images)

“Who Killed the Lyon Sisters?” airs Saturday, Nov. 28 at 9 p.m. EST on ID. The Associated Press contributed to this report.