By 6pm, police national dive squad members found what is believed to be his body, in the water just metres from where the cap was found.
Eastern Waikato police area commander John Kelly told the Herald the body is still subject to formal identification but they believe it is Cochrane and his family have been informed and are understandably distraught.
He also clarified that the hat had been sitting on the fence after it was found by the property owner who thought the owner would walk back past and collect it.
Cochrane's family issued a statement tonight saying they were "saddened but relieved to have Luke returned to us".
"The people of Mercury Bay and local businesses - far too many to name - have humbled us with their overwhelming kindness and generosity in our moment of need," they said in a joint statement.
"Police and Search and Rescue, along with family and friends and many volunteers who didn't even know Luke - we give you our heartfelt thanks for your love and support."
Cochrane's death is now in the hands of the coroner.
Although they are upset, Kelly said the family were thankful of the support by the Whitianga community who had been turning up in their droves dropping off food - everything from cakes and slices to chairs and sausages for the bbq - at the LandSAR base on the outskirts of town.
All around town local businesses had done all they could to help by posting Cochrane's 'missing' poster on their front windows, while others were carrying out their own searches by walking areas of interest.
A local dive shop had donated oxygen tanks to the dive squad so they didn't have to bring them up from Wellington, while a five-strong team from Hot Water Beach Surf Lifesaving Club were helping assist them in their water search.
It's been a humbling community effort all round.
And while the Cochrane family now have to deal with their heartbreaking loss, they at least will hopefully now have some closure and be able to say farewell to their loved one.
