Two designers of the CTV building are to be interviewed by police as part of a criminal investigation into the building's collapse in February 2011, which killed 115 people.
The six storey building pancaked during the February 2011 Christchurch earthquake killing most of those inside.
Alan Reay and David Harding were heavily criticised in a report by the Royal Commission of Inquiry into the Canterbury Earthquakes for their involvement in the design of the building.
The CTV site Photo: RNZ / Diego Opatowski
The police said the services of an engineering firm were engaged to determine if those involved in designing and constructing the office block had departed from accepted standards and if this could amount to gross negligence.
They said most of this report had been completed and they have reached the view that a further criminal investigation is warranted.
