Mr Anderson would not say when or where the Jeep was found except that it was located in the Bay of Plenty after a tip-off from a member of the public.
He said it was found "complete, in a normal state" and that a forensic investigation would continue for up to two weeks.
Mr Anderson would not say if any items of interest were found in the Jeep or whether the weapon had been found.
The Jeep led police to the suspect, who is one of several interviewed by detectives in the past four weeks across the Rotorua and Taranaki districts.
"Finding the Jeep was the key to this investigation and that's opened the door really and allowed us to narrow the focus of this inquiry."
The main suspect, who might not be aware he is atop the police list for the killing, did not have a "familial relationship" with 67-year-old Mr Taiaroa, Mr Anderson said.
However, he would not comment on whether the man was known by the Taiaroa family.
When asked what the family's reaction was to the finding of the Jeep, Mr Anderson said he spoke at length with Mr Taiaroa's widow, Helen Taiaroa, on Tuesday.
"She is very appreciative of the work done. The family still remain strong. I'm amazed about how strong they are and how they've dealt with this tragedy in their lives."
On Thursday the investigation team swooped on a rural Rotorua farm and a 76-year-old man was arrested on a firearms charge.
Mr Anderson said the arrest and charge was not related to the homicide inquiry and amounted to a storage misuse offence.
The charge would not go to court, however Mr Anderson would not rule out that the incident was relevant to the inquiry.
Mr Anderson said police were still seeking sightings of the Jeep and the person driving it on and leading up to March 19 in Benneydale, Taranaki, Stratford, Taumarunui and Rotorua.
When asked if an arrest was imminent, Mr Anderson said the team had to be "extremely thorough".
"These cases are tested in the High Court and we have to be as thorough and as detailed as possible, but also patient."
