Timeline: CTV building collapse

It's been nearly seven years since the 2011 earthquakes, and a police investigation into the CTV building collapse has been running since December 2014.

The six-storey office block was flattened in a matter of seconds during the earthquake.

People were either crushed to death or died in the fire that followed.

A Royal Commission found major faults with the building's design that was completed by structural engineers, Alan Reay Consultants Limited.

The police raided its offices over two years ago, and removed documents as part of their investigation.

In October 2017, the inquiry head, Detective Superintendent Peter Read, said the issues before them were finely balanced and that police would weigh up legal advice before making a final decision.

Police have been conducting an investigation into whether criminal charges can be laid following the collapse since December 2014.

Timeline:

• 4th September 2010: Christchurch is hit by a 7.1 magnitude earthquake at 4:35 am, causing widespread damage and power outages.
• 5th September 2010: A level-one inspection is carried out on the CTV building. It was given a green sticker meaning 'safe to occupy'.
• 7th September 2010: Three Christchurch City Council officers carry out a level-two inspection - which usually requires an engineer to be present. The building is again given a green sitcker even though an engineer had not assessed the building.
• Late 2010: The building manager arranges for a chartered professional engineer to inspect building. They carry out three inspections and email the building manager to confirm the building is structually sound. Further assessment recommendations were also given, but were not later carried out.
• Boxing Day 2010: A 4.9-magnitude earthquake causes further damage to the building. It is again given a green sticker.
• 22 February 2011: Christchurch is hit by the 6.3-magnitude earthquake that killed 185 people. The CTV building collapsed in seconds, and 115 people were either crushed to death or died in the following fire.
• Feburary 2012: The Housing and Building Department finds the CTV building did not meet prevailing standards when it was built in 1986.
• June 2012: An inquiry hears that the concrete in the CTV building had the consistency of chalk, the structure lacked toughness, and the post-2010 earthquake inspections were rushed.
• August 2012: The CTV building's principal engineer Alan Reay tells an inquiry the building was not up to scratch, and apologises to the families of the victims. During the inquiry, Mr Reay maintained he had little to do with the building's construction.
• August 2012: A Royal Commission into the CTV collapse heard the building construction manager Gerald Shirtcliff, "wasn't up to the job", and rarely visited the construction site.
• October 2012: It emerges that Gerald Shirtcliff was being investigated for identity theft and using a stolen engineering degree.
• December 2012: Fire services deputy national commander Paul McGill apologises for the intial response when the building collapsed after an inquest into the death of eight people who initially survived but later died. Mr McGill said some of his staff had been inadequately prepared.
• February 2014: Alan Reay resigns from the Institution of Professional Engineers New Zealand (IPENZ) but remains a chartered and professional engineer. The building's designer, David Harding, also resigns from IPENZ.
• July 2014: Families of victims tell a one-day disciplinary hearing the CTV building was "designed by an incompetent engineer, supervised by an irresponsible engineer and constructed by a fake engineer".
• August 2014: Gerald Shirtcliff is fined $A500,000 in Queensland after pleading guilty to 146 charges of carrying out professional services while not a registered engineer, and making false statements to the Board of Professional Engineers of Queensland.
• September 2014: Police say they will advance a criminal investigation into the building's collapse.
• November-December 2014: IPENZ finds David Harding had inexperience in designing multi-story buildings and had misrepresented his ability. He was suspended from the register of Chartered Professional Engineers after failing to mention in his application for reassessment that he had designed the CTV Building in 1986. He was suspended and fined $10,000.
• June 2015, Police raid Alan Reay's offices as part of its investigation into the CTV building's collapse. Detective Superintendent Peter Read says the investigation involved consideration of a large amount of complex, technical information which would inform police on recommendations about any criminal liability.
• September 2015: Police say they hope to complete their investigation by the end of 2015.
• December, 2015: Police say the investigation will continue into 2016.
• 5th October 2017: Police say the outcome of the investigation is "close".
• 30 November 2017: A survivor says police confirmed to him they would not lay any charges over the CTV Building's collapse.