Detective Senior Sergeant Glenn Barnett, the officer in charge of the subsequent homicide investigation, said evidence collected since Lois' death has confirmed that Tolley was targeted that night by her killers.
"Lois' killing was an absolutely tragic and senseless crime," says DSS Barnett.
"Sadly, Lois had become involved in the Upper Hutt drug scene and her death appears to have been connected to that world."
Barnett said police were not sure whether she was dealing drugs, but that they were found in her home.
"We believe that the four people who came to her home that night were attempting to carry out some form of 'taxing' or debt collection, or that they were looking for drugs/cash for their own use.
"In the moments after the four attackers smashed their way into her home, Lois was left dead, neighbours were threatened, and drugs and cash were left behind."
Lois Tolley was shot at point black range. Photo / Facebook
Police have spoken to many people during the investigation, including hardened criminals and gang members.
On the night of the attack, police say one of the attackers appears to have shown remorse, allegedly shouting "what have we done?" before the four ran into the dark of the night, never to be seen again.
"Lois was no threat to anyone, and even the most hardened criminals and gang members have said her death was a cowardly act and completely unnecessary," said Barnett.
Police have spoken to more than 130 people of interest over the past two years, with new names popping up and old names eliminated from the investigation altogether.
But now investigations have taken police across the Tasman to Australia where they have talked at length to associates of Tolley's attackers.
"The inquiry team has spoken directly to close associates of the four individuals involved," said Barnett.
"They have told us that they know what happened and who the attackers are.
"While some of these associates are unwilling to provide formal statements, there are some who have provided formal statements, allowing us to build a solid group of witnesses who are signed up to give evidence when we're able to bring the case to court.
"We know that as well as the four individuals directly involved in the events at Lois' home that night, there are others who were involved either directly before or after her murder. We also believe that there are others who have information which could help us close this case, who have not yet spoken to us.
"There are a number of people who are nervous about speaking to police or providing us with a formal statement, for any number of reasons.
"It could be that they are in a difficult position due to perceived loyalties to those involved. Or they may just not like police.
"To those people, I would urge them look past their nerves or antipathy to police."
Flowers at the scene in Upper Hutt house where Lois Tolley was found murdered on December 12, 2016. Photo / Georgia Nelson
Barnett said on Newstalk ZB this morning that police were confident they would be making an arrest in the case, and that it would be within a year.
Operation commander Detective Inspector Scott Miller said six people had been interviewed in Australia, including a man and woman of interest - one of whom was a witness.
"A number of people of interest went overseas either soon after the murder, or after they were spoken to by police.
"A number of those people have been spoken to by Australian police, and members of the Operation Archer investigation team have travelled overseas for interviews.
"Some very interesting information has been gained as a result of these overseas inquiries.
"All those involved should know that it is only a matter of time before we knock on their door.
"It might not be today, and it might not be tomorrow, but I remain confident that we will get the evidence we need to charge those involved in Lois' death."
"They stole her future away from her and have devastated ours.
"It is so hard not hearing her voice and seeing her beautiful smile.
"We know that Loie was not perfect – nobody is – but Loie was our perfect."
Anyone who has information that could assist the investigation into Lois' death is urged to contact the Operation Archer team at Lower Hutt Police Station on 04 560 2600.
Information can also be provided anonymously via Crimestoppers on 0800 555 111.
