A death investigation and missing person case has been unfolding in Georgia that’s unlike anything local authorities have ever seen, with cops spending nearly a month looking for the fiance of a Spelman College instructor who was found dead and floating in a lake, along with her partner’s boat and shoes. The U.S. Secret Service has even been called in to assist, according to officials.

“There’s never been anybody looked for like this,” Putnam County Sheriff Howard Sills told local Fox affiliate WAGA this week as police entered day 22 of looking for Gary Jones, husband of Joycelyn Wilson, at Lake Oconee — the last place they were seen alive together — in what officials have dubbed the largest search effort in county history.

Jones, who is believed to be dead, was boating with Wilson on Feb. 8 when they disappeared sometime that evening. His boat was found circling a portion of Lake Oconee with no one on board, roughly seven miles away from where he and Wilson were caught on video at a boat launch. Cops say they can be seen putting the vessel into the water together. Witness testimony and phone records show that whatever happened with the couple unfolded between 5:01 p.m. and 5:24 p.m., according to Sills.

“This is a huge area,” he told Fox and ABC affiliate WGXA last week. “Not to mention the cold weather and the cold water preventing normal surfacing. There is a Herculean effort going on here trying to locate his body.”

Authorities fear the worst after recapturing three jail escapees — the men allegedly stole a yacht and might have killed a missing sailor couple.

“The RGPF is currently working on leads that suggest that the two occupants of the yacht may have been killed in the process,” the Royal Grenada Police Force wrote on Thursday. “It is believed that the occupants of the yacht were American citizens.”

Loved ones identified the missing sailors as Ralph Hendry and Kathy Brandel, a married Virginia couple in their 60s who had been enjoying retirement on their boat, “Simplicity.”