Mr Winkel worked for the last four months of 2013 as a volunteer at Waiohika Estate, helping with preparations for the Feast wine and food festival and the Rhythm & Vines music festival.
Police have reconstructed what the group were doing and what led up to the firearm being discharged.
The accident occurred as the three hunters walked together across a paddock.
"It was fairly flat terrain," said Detective Senior Sergeant Craig Scott.
Mr Winkel's companions were interviewed the day after the shooting.
"We will be assessing the information gathered as part of the inquiry.
"No decisions have been made yet on whether or not any charges will be laid."
Mr Winkel is now living in another part of New Zealand and his family have returned to Germany.
His parents arrived to be with their son in the days following the accident.
- The Gisborne Herald
