The Gabby Petito case could be more complicated than it may appear on the surface -- and part of the reason is figuring out where exactly she was killed.
Law enforcement sources tell TMZ ... investigators are currently trying to figure out if Gabby was, in fact, slain where her body was found a couple weeks ago -- which was in the vicinity of Grand Teton National Park and the Bridger-Teton National Forest Service in Wyoming.
That's all federal land ... and, at the moment, the FBI is running point. However, we're told if it's determined Gabby wasn't actually killed on federal land, then the case would be kicked over to the state authorities in charge. The big question: If it's uncertain, who has jurisdiction to prosecute the killer?
Sources connected with the investigation tell TMZ, if there's no way to determine where Gabby was killed, the default will be where she was found, and since it's on federal land the U.S. Attorney would prosecute the accused killer. If, however, there's ambiguity and state authorities believe her body was moved there, the state and the feds could be at odds.
Meanwhile, Brian Laundrie is still on the loose and unaccounted for -- and his family doesn't seem to be of much help at this point in getting answers.