Victims' distraught families want police to find who is responsible for the substandard Canterbury Television building that collapsed in the February earthquake, killing 115 people.
A damning investigation by the Department of Building and Housing (DBH) has found the six-storey building fell short of the required building standards when constructed in 1986, and the findings have now been passed to the police to consider if anyone may be criminally liable.
Karen Bishop, whose son Andrew, 33, died in the collapse, said she was disgusted to learn the building had not been up to scratch from the beginning.
"I just want to know if they were penny-pinching. There's criminal negligence going on there somewhere, and if [police] can home in on it and pinpoint it, I applaud them."
The report showed that the victims didn't need to die, Ms Bishop said. "Someone has to be answerable for this. For God's sake, it killed 115 people and it should never have happened."
The DBH report found the building's concrete columns were brittle and would have failed under the stress of the 6.3 magnitude quake, while its shear (stabilising) walls were not symmetrical and would have caused the building to twist more than normal.
Report project manager Dr David Hopkins said that if the CTV building had been constructed to standard, it would have had a "much better" chance of surviving the quake.
But one of the firms involved with the building when it was first built has hit back strongly at the DBH report, saying some of its content is "highly questionable" and "may be flawed".
Alan Reay Consultants carried out the initial structural design of the CTV building and its principal, Alan Reay, said: "Personally I feel incredibly torn. I have huge empathy for the families waiting for answers, but these reports are technically inadequate."
More thorough investigation was needed to ascertain whether there were failings in the columns and shear walls, Dr Reay said.
"We need to remember that the standards of the day, when the building was designed and constructed, were not intended to withstand the magnitude and type of earthquake ... experienced on February 22."
Gerardo Torres, whose sister Elsa Torres De Frood was killed, said last night, "My heart is broken." He wanted the person responsible for the design to explain himself.
Geoff Brien lost his wife, Pamela, and just wants someone held responsible. "I don't care who it is. It's up to the Government and the police now and I hope they bust some arses."
David Beaumont, who lost his son Matthew, 31, said: "No one would deliberately build a building that would lose 115 lives. People have been careless and that is as far as you can go, and that degree of carelessness needs to be investigated by the police.
"People, if they have done something wrong, have got to live with their conscience."
Anne Malcolm, one of the badly injured CTV survivors and mother of Outrageous Fortune star Robyn Malcolm, said she believed the "extraordinary forces of nature" were behind the collapse.
"Shock and dismay are the overwhelming feelings at the moment. I'm sure there will be a complete range of feelings that will emerge for the huge number of people whose lives have been changed forever.
"Those of us in the building completely trusted its safety. We were completely unaware there was something flawed.
"It certainly didn't occur to me that something like this had happened in that building that looked so solid and strong. That's why we have building standards, so there are standards that are met."
The DBH report examined several possible collapse scenarios and concluded the common factor in all was that "one or more columns failed because of the forces placed on them by horizontal movement between floors".
"The asymmetry of the stabilising walls meant the building would have twisted during the earthquake, placing extra strain on the columns."
Former tenants of the building had raised concerns that it was at risk of collapse as a result of damage in the first big quake in September 2010.
But the report said any damage then, and in the Boxing Day quake that followed, was only "relatively minor".
The CTV building was built for a developer in 1986 by Williams Construction, which went into liquidation.
Yesterday, building owner Madras Equities refused to comment on the DBH report. But director Lionel Hunter has previously said he lost a good friend in the building's collapse.
"If we had known anything was wrong with the building, I would have pushed it over myself."
Assistant Commissioner Malcolm Burgess said an initial assessment of the evidence could lead to an investigation and criminal charges, but it would be wrong to suggest that would naturally follow.
The police would first seek legal advice on the report. The threshold for establishing criminal liability was "extremely high", Mr Burgess said.
If liability could be established, potential offences would include criminal nuisance - which covers negligent acts leading to harm - and manslaughter.
DBH chief Katrina Bach said her department had not looked into laying blame in its investigation or establishing who might be responsible for the building's not being up to standard.
But she added: "There are findings that are of concern and it is important that they are made transparent and are passed onto those who have the authority to take matters further if they so choose."
Top civil action lawyer Grant Cameron said bringing legal action on behalf of the victims' families might be "problematic" under New Zealand law, but was not impossible.
IN FIRING LINE
* Williams Construction, the builder, but it has gone into liquidation.
* Alan Reay Consultants Ltd, which did the initial structural design.
* Christchurch City Council, which issued the building consent.