Police are making a fresh appeal to the public for information about two fires in relation to the death of Margaret "Terri" Fordham, who died in August 2021 after a fire started at her property in Upper Hutt.
The 75-year-old was upstairs asleep with her dog Daisy during the time of the fire and woke up during the blaze to call for help.
Fordham's neighbours tried to rescue her using a ladder but couldn't get to her in time.
"Terri's last act was to throw her dog Daisy to safety before she succumbed to the smoke," Detective Sergeant Sam Mercer said in a statement.
Just two nights later, neighbours were woken by another fire at the same Upper Hutt address.
No one was in the house during the second fire.
Det Sgt Mercer said they are making a fresh appeal to the public as it has been a year since Fordham's death.
"We believe that a person or persons have entered the burnt-out property in the early hours of that Saturday morning and deliberately set fire to the second storey.
"We are following up every possible line of inquiry to identify that person, but we need the help of the public who might hold important information."
Det Sgt Mercer added the person in question may have spoken to a friend or family member about the fires.
"This is a really tragic situation in which a much-loved mother and friend has lost her life," Det Sgt Mercer said.
Fordham's son Kester said in a statement that he wants to be able to mourn the death of his mum properly.
"Nothing is going to bring mum back, or fix it, but finding out what happened would help us understand why, rather than just being left wondering, doubting and questioning things."
Police are encouraging anyone with information to contact them on 105, and quote the file number 210812/6583.
If they wish to remain anonymous they can provide the information through Crime Stoppers by contacting 0800 555 111.