Chris Kahui says he didn't kill his twin babies, but he thinks police believe he did.
The father of murdered twins Cru and Chris Kahui also told the Sunday Star-Times he has separated from the twins' mother Macsyna King due to the pressure of the police investigation.
Mr Kahui, 21, said he thought he would be arrested if police didn't find the person responsible for killing the babies shortly.
"If they don't find the person, it's ... basically sure. That's what I say. In the end I go down for something I didn't do.
"If I had known the person who did it, of course I would have done something, because those are my babies."
Mr Kahui confirmed the family had agreed not to talk to police during the inquiry.
He had given two statements to police but had not talked to police directly on legal advice for two weeks.
"I can't talk to the police because anything I say can be used in evidence against me.
"They can say 'Oh, you did it.' I'm just going with what my lawyer says."
Mr Kahui said he split from Ms King two months ago, partly because the couple were accusing each other of being responsible for the twins' deaths, but that he still loves her.
"She's the mother of my kids, she'll always be a part of my life.
"In a way I was blaming her; we were blaming each other."
Three month old Cru and Chris died in Starship Hospital in Auckland on June 18 after being admitted five days earlier.
Mr Kahui said he had his own difficulties at the time the babies were injured as his mother Gwen Hetaraka was extremely sick in hospital with pneumonia.
He said Ms King left him alone to look after the boys the day before they went to hospital, and he went to feed them every four hours with his sister until 1am the next day.
He went to buy milk formula between 6am and 7am, and on his return found Ms King there, after which they had an argument about Ms King's absence.
Mr Kahui said he went for a walk to cool off, and on his return they agreed to take the babies to the doctor.
He said he "freaked out" when he discovered the babies were in intensive care.
The babies died five days after they were taken in. They had massive head injuries and broken ribs, and one had a broken femur.
He said anyone in the family could have given the children their fatal injuries.
"I'm not going to say this person did it because I can't say I saw somebody do it because I didn't.
"I want it to go away. Really it sucks. Let me get on with my life. I want to start again."