CTV building collapse: Probe taking longer than expected

The CTV building collapsed in the February 2011 earthquake, killing 115 people. Photo / Geoff Sloan

The police probe into the deadly collapse of the Canterbury Television building in the February 2011 earthquake is taking longer than police expected, and could still not be concluded by the tragedy's fifth anniversary.

The complex technical criminal investigation is yet to find whether anyone will be charged with the building's pancake collapse, which claimed 115 lives.

Investigators have interviewed more than 100 witnesses and raided the offices of Engenium Consulting Engineers, formerly Alan Reay Consultants, which designed the ill-fated Christchurch office block in the mid-1980s.

In September, police announced that they were working with engineering consultants Beca and making replicas of the structure to test its critical elements.

Today, Detective Superintendent Peter Read confirmed the investigation is ongoing, with no decision expected until next year.

The physical re-build and testing of critical elements of the building structure has "taken longer than anticipated to make the necessary arrangements ... given it involves complex technical matters involving outside experts," Mr Read said.

Police now expect to receive the full analysis of this testing early next year.

"Once all the relevant information is to hand, police will be in a position to make final decisions regarding any criminal culpability," he said.

"We reiterate that this is a very complex inquiry, and the focus is to ensure a meticulous approach is taken to gathering the necessary information required by the inquiry team."

Police say they are unable to put any firm timeframes on when a final decision will be announced, however they anticipate providing a further update in the first quarter of 2016.

The victim's families have been advised.

The six-storey concrete CTV Building pancaked in the vicious magnitude 6.3 quake on February 22, 2011, claiming 115 lives.

In 2012, the royal commission of inquiry found serious errors by engineers, structural designers and the Christchurch City Council.

After the report's release, families and friends of the victims called for legal action to be taken against those responsible.

The commission said Dr Reay should have recognised that his employee David Harding was working beyond his limits when designing the building in 1986.