Where IS Gabby Petito’s missing fiance? Survival expert’s chilling new theory on Brian Laundrie

For more than three weeks, local and federal authorities have been combing through a 25,000-acre nature reserve searching for Brian Laundrie, the fiancé of 22-year-old Gabby Petito.

On September 1, Laundrie returned in Petito’s van to the couple’s North Port, Florida, home from a…