As they crawled and clawed through the muck and algae Tuesday, two men in diving masks and wet suits discussed their theories on where someone could dispose of a body in the stagnant pond.

The sheriff’s deputies poked at the bottom of a 10-foot-wide, shrub-choked channel that separates the shore from the pond’s open water. They threw aside sticks and handfuls of green slime. They remarked at the stench.

“In order to get out there,” one diver said.

“He would’ve had to get through here,” the other said about the channel, finishing his partner’s sentence.

On their mind was the case of Gayle McCaffrey, the mother who went missing almost exactly a year ago from her home about 5 miles away from the pond off Bear Swamp Road in West Ashley.

But their operation wasn’t in search of specific clues. They were not acting on tips, according to the Charleston County Sheriff’s Office.

The effort’s connection to the investigation was tenuous: its proximity. The divers needed to hone their techniques, so they practiced in an area where McCaffrey was thought to have disappeared and hoped to stumble across some evidence.

“We felt that it wouldn’t hurt to maximize the effort ... to see if it would be any benefit,” sheriff’s Maj. Jim Brady said. “Any time you can use a training function to assist a case, then we would do that.”

To scout out prime diving spots, the crews skimmed the pond Monday with a sonar-equipped boat, Brady said. They returned to the pond for about two hours Tuesday.

The pond is just northwest of the intersection of Bees Ferry Road and U.S. Highway 17. Deputies and volunteers have conducted several operations in the area on foot, but each has come up empty.

Such was also the case with the training exercise.

The divers uncovered nothing and carried away from the pond only the gunk that clung to their gear.

It has been a frustrating probe for sheriff’s detectives who have long considered the woman’s husband, Bob McCaffrey, as the suspect in her presumed death. But they have developed no solid evidence to make an arrest.

A call placed to his attorney, Chris Lizzi of North Charleston, was not returned Tuesday.

During the weekend, authorities released photos of his Dodge pickup and her Jeep in hopes that someone would remember seeing the vehicles on the night when the Citadel employee was last seen. Brady said that someone’s observations might seem insignificant to them but could help deputies.

But again, he added, the public plea wasn’t in response to any new information investigators had dug up.

Bob McCaffrey reported his 36-year-old wife missing on March 18, 2012, at the urging of his family.

Family members reported that the couple had engaged in an argument the night before. He left for a quick overnight trip to the Upstate to see a love interest, the Sheriff’s Office has said.

When he returned, he told deputies, McCaffrey found his two children asleep and his wife gone.

“When we’ve reached the point where we’ve made a charge and located Gayle McCaffrey, we’ll give up on the case,” Brady said. “Then we won’t give up the case until it’s prosecuted.”

Reach Andrew Knapp at 937-5414 or twitter.com/offlede.