Joe Cochran is a former sheriff of Gunnison, Colorado.
In 1989, people in the town began disappearing without leaving a trace, among them was Matty Cuevas. While Joe was able to track down and locate the monsters responsible - which turned out to be bisaan - he realized one of the monsters had taken possession of his own daughter. Joe was forced to kill her, and the guilt drove him to want to cover up his actions.
Since Joe believed the bisaan to be a dying race, he lied about their existence, leading everyone in the town to think Matty's brother Jesse, who saw the creature, to be insane. Although the disappeared locals were dead, Joe chose to convince the townspeople that their loved ones had likely run off to enjoy a better life.
Approximately 30 years later, in 2016, Joe Cochran was approached by Sam and Dean Winchester, who came to ask about that case, since the disappearances had started up again. When the brothers revealed that they were aware that monsters existed, Joe confessed about his actions, leading Jesse to furiously argue with him, though Joe retaliated by saying that he too had suffered.
Sam and Jesse chose to sympathize with Joe since he still kept a photo of his daughter and began clutching it tearfully. He revealed the location of the bisaan lair, enabling the four hunters - including Jesse's husband Cesar - to destroy the bisaan once and for all.