Norfolk Police have said there were "a number of missed opportunities" in the original investigation "which may or may not have helped to provide further clarity as to the cause of death".
Medics said shaking was the most likely cause of death, but also said there were other internal injuries which may have been caused before the day Tyrone died.
Kelly had a significant degree of coronary artery disease and that this may have played some small part in the speed of death but not a major cause of death, he added.