A crime laboratory will definitively determine whether the remains are those of Shirley Dermond, and establish a cause of death in a case that has perplexed investigators in central Georgia.
The body matches the general description of Dermond and has similar surgical scars, Sills told a news conference. He described the case as a homicide, but he said investigators could not see any obvious signs of trauma on the remains. Authorities suspect the couple were killed May 2 or May 3.
"We now unfortunately know that Shirley Dermond was murdered, and we're no longer, unfortunately, seeking to rescue her," Sills told reporters during a news conference. "As bad as that is, it progresses our investigation."
The sheriff said he hoped a forensic examination of the remains might yield more clues that could assist investigators. Authorities also plan to use an underwater submersible to examine the bottom of the lake for evidence.
The killing was a shocking anomaly in a gated, exclusive community guarded by private security. Police have said they do not believe the violence was random. The couple's lakefront home showed no signs of a struggle or forced entry and no ransom note was left behind.
Sills said the body was discovered five to six miles from the couple's home, raising the possibility that the assailant or assailants may have used a boat to gain access to the property and possibly took Shirley Dermond with them when they left.
"That body was transported there, or at least to that vicinity," Sills said.
Before the discovery of the wife's body, authorities had treated her disappearance as a potential kidnapping, even as they feared she may be dead. They displayed her picture on area billboards in the hope it might generate tips. Sills said investigators have also consulted with agents in the FBI's behavioral unit in the hopes of gleaning insight about who might be responsible.