ATLANTA (AP) — Rescuers searched for a second body Friday, one week after two boaters went missing on a Georgia lake that draws tourists from around the South.

The body of Joycelyn Wilson, a mathematics instructor at Spelman College, a historically black institution in Atlanta, was found Sunday in Lake Oconee.

Her boating partner Gary Jones remains missing. Jones is a track and field coach at the Westminster Schools, an exclusive Atlanta private school community.

Their empty boat had been discovered Saturday night, circling in the water. Jones’ shoes were later found floating in the water not far from where Wilson’s body and the boat were discovered.

Putnam County Sheriff Howard Sills is not describing the case as a boating accident or anything else at this point.

“We have ruled nothing out at this point in time,” Sills told The Associated Press on Friday. It’s not just “a simple drowning,” he added.

The sheriff said he’s awaiting a final autopsy report from the medical examiner. The sheriff’s office has obtained video of Wilson and Jones launching their small boat from a local marina. That’s not far from where they had been staying at The Lodge on Lake Oconee, southeast of Atlanta.

“Lakes and rivers don’t give up bodies until they get ready to,” Sills said. “This is not a rescue operation. This is a recovery operation at this juncture and sooner or later that body will come up.”

A Giant Schnauzer trained to find cadavers has joined the search, which involved about a dozen government vessels and another half-dozen private boats on Thursday. A helicopter and underwater sonar are also being used in the area that includes water as deep as 80 feet (24 meters).

In his more than five decades in law enforcement, “I’ve never seen this many people involved in a search for a dead body before,” Sills said.

“Unless the weather changes to prevent us from being out there, we’ll continue to search,” he said.