An appeal's been dismissed - for a murderer who killed a pregnant Rotorua woman in 2002

John Michael Wharekura, who was 16 when he stabbed Tanya Burr, argues his guilty plea was down to mental illness.

The Court of Appeal has tossed out the case on several grounds - including doubt over his mental health claims.

There were also concerns around the destruction of documents related to the case.

The victim's mother says she's relieved his appeal has failed - but she's shocked he even tried.