Brian Laundrie took his own life before the nationwide manhunt ... at least that's what cops in Florida are saying.
Sarasota County Sheriff Kurt Hoffman told folks in town Brian "went out there and by all accounts probably committed suicide and he was right out there where we thought he was" ... TMZ has confirmed.
Fox 13 Tampa Bay
As we reported ... Brian's remains were found Oct. 20 off a Florida trail near his notebook and backpack, ending a 5-week manhunt after he disappeared in the wake of his fiancée, Gabby Petito's death.
The FBI positively identified the bones found as Brian's, thanks to dental records, but the coroner could not determine a cause of death from Laundrie's remains ... and the bones were sent to an anthropologist for further examination.
Police say the area where Brian's remains were found had previously been under 4 feet of water ... one reason why he was not found sooner.
North Port police chief Todd Garrison also admitted to a "human error" in the search ... explaining cops trailing Brian thought they saw him going back to his parents' house, but mistook him for his mother.