Officer McKernan was found dead from gunshot wounds in an ally near 441 East 11th Street, his revolver and police badge were missing. Officer McKernan left his partner, Officer Michael Barry, earlier that night, stating that he was going to see man with whom he had a misunderstanding. Several people in the area remembered hearing gunshots, but none had looked to see what had taken place. From tracks discovered at the scene it was determined that he ahd been shot in a different location from where his body was discovered. No further information is known.

Officer McKernan had been with the agency for eight weeks and was survived by his wife.