Email firstname.lastname@example.org or contact the police or Crimestoppers anonymously on 0800 555 111 with information on Mr Guy's death.
Kylee Guy is working with private investigators to find out who killed her husband and is asking anyone with new information to come forward.
Ewen Macdonald was acquitted of Scott Guy's murder after a High Court trial, and Mrs Guy has now begun her own investigation.
Auckland private investigators are conducting the inquiry, in partnership with the Sensible Sentencing Trust and police.
Mrs Guy has said she wants to find the killer for "her Scotty" and for his boys - sons Hunter, 4, and Drover, who turned 2 yesterday.
It is understood Macdonald knows of the investigation.
Led by Mike Crawford from Mike Crawford and Associates the team also includes Phil Jones from Omega Investigations, Gary Howarth from Thompson and Clark and Tim McKinnel from Zavest investigations in Hawkes Bay.
It is understood the investigators approached Mrs Guy offering to assist her after the trial.
After the court case Detective Senior Sergeant Sue Schwalger said Mr Guy's death was an "ongoing investigation" and any new information would be considered.
"I would like to make it clear that if any new evidence comes to light, police will investigate it with the same vigour as they have throughout this inquiry," she said.
"Police are currently not pursuing anyone else in relation to this investigation nor are there any other avenues of inquiry."
Mrs Guy paid tribute to her husband during an interview with Woman's Day magazine, calling him "my soulmate, my best friend, my world".
"How can I ever give up? How can you give up on the love of your life? He wouldn't give up on me. And I won't give up on him. I can't, and I won't.
"I still talk about him as though he's there. I do feel though he's still here - he would never leave us.
"I still can't believe it's happening," Mrs Guy said.
"It feels like I'm trapped in a really bad dream. Like ... it's not true. Here we were living our amazing, happy lives and we had no idea."