On Wednesday police said the death of the 53-year-old was not the result of a random attack.
"The people in this incident are known to each other," a spokesperson said.
No arrests have been made.
Corrections confirmed on Tuesday Butler was on a community-based sentence after a request from NZME considered under the Official Information Act.
It is believed Butler was on home detention.
Read more: Police name man at centre of homicide investigation
The homicide investigation was launched the day after Butler as found dead and another man in his 50s was found seriously injured.
Anyone who may have information which could assist in this investigation is asked to contact Police.
Information can be given anonymously by calling Crimestoppers on 0800 555 111.