Waikato police district crime services co-ordinator Detective Senior Sergeant Nigel Keall said forensic work and a post-mortem examination were now finished.
Mr Keall said the post-mortem findings were that Mr O'Connor's injuries were consistent with him suffering a fall.
The matter had now been referred to the coroner.
Mr O'Connor was found by two men who called 111 after finding him unconscious in the northbound lane of Hillsborough Tce.
A resident of nearby Anglesea St said he had heard running footsteps and then a yell of surprise after midnight.
Peter Bell said he believed the man must have come to the edge of the street, which overlooks Hillsborough Tce, without realising it.
A railing and thick shrub surround the cul-de-sac, which drops off down a steep bank without warning.