Just when you thought there couldn't be any more "Tiger King" drama, there's this . . .

JOE EXOTIC's zoo was searched by authorities in Oklahoma on Friday night . . . after an investigation by The Travel Channel's "Ghost Adventures" team led them to believe there were HUMAN REMAINS on-site.  (???)

According to reports, that show was on the property for some sort of "ghost investigation," and they had some cadaver dogs that picked up a scent near an alligator pit.

So the authorities were brought in, and they did some digging.

They weren't able to find any HUMAN remains, but they did uncover some small animal bones . . . so no, they didn't find Carole Baskin's missing husband.

For what it's worth, Joe Exotic has supposedly admitted that the ashes of four people have been buried on the property as a memorial . . . but again, this search turned up nothing, and the case has been closed.