Boston Police Officer John O'Keefe's body was found in the snow at 34 Fairview Road in Canton, Mass., on January 29, 2022. So began a high-profile investigation into his death that revolved around two equally complicated theories.

O'Keefe and his girlfriend, Karen Read, were out drinking with friends on the night of January 28, 2022. A bit after midnight, Read drove the couple to Boston Police Officer Brian Albert's home, where friends from the bar met back up. Around 1 a.m., Read left the house. She left O'Keefe a series of angry voicemails and texts telling him she was "going home."

When ...