MEDWAY, Maine — Small, slight rust spots dotted it. The ornamental plastic sheeting that prettified it was peeling. So were some flecks of silvery-gray paint from along a bubbly water line marring the surface.

But the steel coffin that held Joyce McLain’s body was uncompromised by 28 years of interment in a cement vault in Grindstone Road Cemetery, despite being found floating in several inches of groundwater seepage.

The casket and vault well served McLain and the investigators trying to find her killer, said Lee “Chip” Lamson, director of Lamson Funeral Home of East Millinocket and Millinocket.

A wood or cheaper coffin likely would never have lasted so long, they said.

“Had it failed structurally, we would have found the casket on the floor of the vault,” Lamson said Saturday as the casket and vault were reburied after McLain’s committal service. “That it was floating was a good sign. That’s what we were looking for.”

“The best thing would have been if there was no water,” said Steve Joy, a boom truck operator from American Concrete Industries of Bangor.

Still, the sandy soil, hilly ground, tight coffin and vault seals, and the sturdiness of both constructs, probably made possible the renewed probe into McLain’s homicide, they said.

Working as volunteers, town laborers unearthed the vault Thursday and Joy used the boom truck to lift the vault from the grave. A Lamson hearse took the casket to the medical examiner’s office in Augusta. State police, Lamson said, complimented the volunteers for their professionalism in a delicate, unique situation. None had exhumed a body as part of a homicide investigation.

Lamson’s bill for such services would have been about $2,000, but the funeral home decided to waive charges.

“I talked about it with my brother [Lamson Funeral Home co-owner Mike Lamson],” Lamson said. “We didn’t want to be a stopping block against anything happening.”

Pamela McLain, the victim’s mother, refused Lamson’s offer of a new vault and casket. Against all expert advice, having foreseen that her daughter’s body would yield new evidence, McLain had predicted that the original materials would be good enough to reuse.

“And she was right,” Lamson said.

Not that he argued.

“It’s like she said: The ground was calling out to her,” Lamson said. “How do you get in the way of that?”