When a Rhode Island man went missing in 2020, his family took matters into their own hands after law enforcement seemingly abandoned their constant pleas for help. On the season finale of Crossing the Line, the family of John Cosme sits down with Phelps to share the story of their heartbreaking search and shocking discoveries. And after a shocking video of the night in question is discovered, Cosme's family is left asking: Was it an accident or something more sinister?