An initial line of inquiry was thought to be that Mr Corrigan may have been accidentally shot by a lamper – rogue night-time hunters who use bright lights to target animals.
Mr Corrigan worked as a lecturer in photography and video in Lancashire before retiring to Anglesey more than 20 years ago.
His family issued fresh tributes following his funeral service.
His partner, Marie Bailey, said: “It is impossible to express my deep sadness and shock at the horrific murder of Gerry. He was my best friend and my soul mate. All the time we have been together I have been proud to walk at his side and he stood beside me, always.”
His daughter Fiona Corrigan said: “My dad was a very kind and funny man. He taught me an appreciation of art and nature. There are so many happy moments we shared and I will miss him too much to say.”
Mr Corrigan’s son, Neale, said: “My father was a wonderful man who cared so much for people.
“My dad believed in the good in people and in life, and in the importance of family, friendship and love. He taught me that we can change, that to forgive brings freedom, and that we should believe in the best in people as no-one is perfect.”