Peter Warren was the resident of a coastal town where sightings of a ghost ship were reported.
Aware of the 37-year cyclic phenomenon surrounding ghost ship sightings, Sam and Dean traveled to town to investigate the dry-land drowning death of Gertrude Case's niece, Sheila. They reported to the Warren residence, the scene of a second death in the area, posing as local police. They arrived just in time to hear Peter recalling to Bela (posing as a reporter) that his brother had seen a ship shortly before he died. His death had been deemed a drowning by the local police, which Peter found implausible. The boys abruptly ended Bela's interview of Peter, to her annoyance, but picked up her line of questioning with him and asked if his brother had described the ship he'd seen. Peter told them about the vessel in rather minute detail, prompting Sam to remark about how he could so precisely describe a ship that his brother had seen. Peter replied that he had seen it as well, as he and his brother were night diving together at the time.The boys later argued with Bela about trying to save Peter, with Bela deeming Peter to be "cannon fodder" who couldn't be saved in time. The Winchesters were determined to save him, however, and staked out near his mansion to keep an eye on him. As they watched him, Sam looked over his research about the Warren brothers, which showed that they had inherited a $112 million real estate fortune when their father died six years earlier. Since he could find no negatives in their history, they still couldn't figure out why the Warrens had seen the ghost ship. As they talked, Peter spotted them and became furious that they were watching him, and called them out about impersonating cops. They unsuccessfully tried to get him to calm down, and he ran to his car to leave. As he tried to drive away, the car stalled. He looked in the rear-view mirror and saw the Sailor's ghost staring back at him. When the ghost touched his cheek, water started pouring inside the car and out of Peter's mouth and he began to choke. The car doors locked and Sam and Dean saw the ghost as they tried to get the doors open. Dean blasted through the window with rock salt and the ghost dissipated, but not before Peter slumped onto the steering wheel, dead.
The Winchesters eventually determined that those who had died before seeing the ghost ship (identified by Bela as the Espírito Santo) had done so because they'd spilled the blood of their own family, as the ship's captain had done to his brother, whom the boys recognized in a photo as the ghost that drowned Peter. The Warren brothers had apparently murdered their father in order to come into his real estate fortune.
Bela was eventually revealed to also be a member of the group of people responsible for the death of family. Knowing that the ghost sailor would come for her, Sam conceived of a plan by which he summoned the spirit of the Espírito Santo's captain at the same time, in order to affect its merging with that of his brother. His plan worked, and both spirits were dispatched.