In a decision released this week, the New Zealand Parole Board found Namana had used his time in prison well, but there was a risk he could re-offend.
It is common, and completely understandable, for victim's families to oppose moves to grant parole to inmates convicted of violent crimes.
It's a valid response towards someone who has caused unthinkable emotional harm and distress - especially if the perpetrator has shown no signs of remorse or any willingness to change.
The latter doesn't, on the face of it, appear to be the case with Namana.
Now 38, he has held a minimum security classification since July 2014 and has been misconduct-free since the beginning of 2012.
He has completed a drug treatment programme, achieved some unit standards in subjects as varied as introductory furniture making, carpentry, horticulture, engineering and laundry work and is currently working with the Puppies in Prison programme and resides in the inner self-care unit.
Horton met him about six years ago, as part of a restorative justice process and felt he was trying hard to change.
To her credit, Horton can see past Namana's horrific crime, and the pain he has caused.
She says she hopes he isn't being kept in jail longer just because he had killed a police officer.
"Would he have been given parole had Murray not been a policeman? If that's the case, that's not okay. No one deserves to die whether they are a butcher or a policeman."
Essentially, Horton is expressing concern about whether or not the killer of her former partner is treated fairly by the justice system.
It's a remarkable example of compassion.
