THIBODAUX, La. (AP) — Authorities say a pilot and a passenger are presumed dead after the crash of a helicopter in a south Louisiana marsh. Authorities in coastal Lafourche Parish say they got a call from a person who saw the helicopter going down Friday morning. The wreckage was found Friday afternoon and and officials say most of the helicopter was submerged in the marsh. No bodies were immediately recovered as of Friday afternoon. The Coast Guard said a privately held helicopter operator, Rotocraft Leasing Co., had alerted the agency that the aircraft was overdue with two people aboard. The company had no immediate statement on the crash.