Brian Laundrie fled into the woods looking incredibly upset -- but his parents still don't know why, or what may be written in his recovered journal ... so says their attorney.
Steve Bertolino tells TMZ ... Brian's parents, Chris and Roberta, have no idea why their son fled with such angst the day he went missing in September. he would only say they felt he was "out of sorts."
Obviously, everyone wants to know exactly what the parents knew and when -- but Bertolino insists they were in the dark on what the heck was happening with Brian as he fled from the house and vanished.
He says ditto on what might be in Brian's journal, which authorities found near his remains at the Myakkahatchee Creek Environmental Park. Bertolino says cops haven't made the Laundries aware of its contents yet -- but says he has heard some of it may not be salvageable.
Of course, that leaves a lot of unanswered questions. Like, for example, how did Brian die, and what involvement, if any, he had in Gabby Petito's disappearance and death.
Bertolino says this is a tragic ending for both families, and claims his clients don't have any more info to help law enforcement solve the outstanding mysteries.