Andrew Tepania was 12-years-old when his mother Edwina Graham was killed by her partner.
In 2002 Edward John Tapsell poured petrol over the 30-year-old and set her alight.
She had three children.
Tapsell was sentenced to life imprisonment for the crime, at the time it was described as one of the worst homicide investigations detectives had worked on.
Since then Mr Tepania has struggled with his mental health and substance abuse.
"I really thought I was going to be something, bit more, had a dream and yeah life changed", he says.
He managed to get a job and support his young family, but struggled with the horror of what happened that night.
And in 2016 those memories came flooding back when he came face-to-face with his mother's killer at a tangi near Auckland.
Last month it happened again when Mr Tepania was shopping for his children in Tauranga.
"I called out to him to confirm it was him, he looked and turned around and started walking towards me."
Mr Tepania claims Tapsell laughed at him and kept approaching.
"I pushed him to get away and he goes, 'who are you' and I said 'bro, you killed my mum'."
Mr Tepania says he punched Tapsell and called police.
He told 1 NEWS that he should've been notified under the Victim Notification Register that Tapsell was in Tauranga, but he says that didn't happen.
1 NEWS put those claims to the Department of Corrections.
In a statement Acting Central Regional Manager, Scott Walker says, "I would like to take this opportunity to unreservedly apologise to Mr Tepania for any distress that has been caused.
"I have contacted him personally to apologise and to advise him of the action we have taken to prevent this from happening again", he says.
Corrections says Tapsell was granted permission to visit the Bay of Plenty, and says Mr Tepania's "registered address at the time was not in the Bay of Plenty".
Mr Tepania had been involved a number of agencies and believed his most recent Bay of Plenty address would be on the register.
But the databases are not connected to keep victims safe.
Corrections says as soon as it knew Mr Tepania was in Tauranga it immediately offered support.
Mr Tepania has now moved again and says he wanted to share his story so others don't experience a similar situation.