(HOUSTON) — A final canvass was performed on the plot of land on the outskirts of Houston, Texas, where the remains of a murdered couple were found in January of 1981 which led to the disappearance of their daughter for more than 40 years.

Two search dogs correctly and independently indicated the area where the bodies of Tina Linn and Harold “Dean” Clouse were found 42 years earlier on Thursday, and investigators bagged a few items and a soil sample.

The main motivation for the search of the land was to give the green light for its future occupant, a convenience and fuel development, to break ground. But it was also to check, one last time, for any clues to the unsolved mystery of the murders of the couple who police believe were likely killed between December 1980 and January 1981.

The case returned to the headlines in 2022 when the couple’s small child, Holly, who had been understood to be missing since the couple was publicly identified in 2021, was found alive in Oklahoma. While many questions regarding the nature of Holly’s disappearance remain, it is known that she was adopted at an early age and is now a mother herself.

A foggy morning ushered in a remarkably clear day in Houston ideal for the four search dogs and their handlers, as well as a band of 12 Texas attorney general investigators to comb through the densely wooded swath of land and the Harris County Sheriff’s Office provided scene security.

The plan for the search involved an initial single-blind K-9 search, where both the dogs and their handlers were unaware of the exact location where the bodies were discovered within the 15-acre plot. This measure prevented either party from entering the scene partial to one area, which protected the integrity of the investigation.

According to Krystal Thompson, a Texas Parks and Wildlife game warden, the canines were trained to indicate scents of decomposition as old as from the Civil War era. Sgt. Rachel Kading, the lead investigator, demonstrated that this could equate to anything from an article of clothing with blood on it, to a human remain like a bone.

After the dogs finished, investigators focused their search on the zone where the bodies were found, using metal detectors, rakes, and other manual search equipment.

“Our goal for today is to make sure we’ve done all that we can to recover any evidence in this case,” Sgt. Kading said to ABC News.

Sgt. Kading stressed the dual-agency effort between her own organization, the Texas Attorney General’s Office, and local law enforcement.

“It’s a cooperative investigation; we’re working together for a common goal,” she said.

The investigator admitted it was “a long shot” that they would find anything, due to the sheer time elapsed, damp weather conditions of Houston, and local wildlife.

Mindy Montford, senior counsel for the attorney general’s specialized unit, echoed her colleague.

“It’s a cold case, so yes, this is a long shot. It happened in the ’80s and now it’s 2023. But in cold cases often you only have long shots. We owe it to families to check every box and so we’re checking this box,” she said.

While the canvass did not turn up overt evidence law enforcement searched for, Montford told ABC News they will consult with a lab regarding the samples they retrieved and if needed, return to the land before it’s developed. In the meantime, they also asked for the public’s help.

“If anyone remembers anything or has heard anything, no matter how small, report it. You can remain anonymous, just please let us know,” Montford said.

Harris County Sheriff’s Office did not respond to ABC News’ request for comment.

The Texas Attorney general’s office is asking anyone with information pertaining to this case to please contact its Cold Case and Missing Persons Unit at coldcaseunit@oag.texas.gov or at 512-936-0742.

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