Tokyo's Ota Ward began an investigation Friday into the quake-resistance strength of a condominium complex that architect Hidetsugu Aneha said was the first project in which he doctored quake-proof data.

Grand Stage Ikegami, built by condo developer Huser Ltd., was finished in June 1996.

In his Diet committee testimony, Aneha said under oath that the complex was the first case in which he lowered the resistance specification to reduce construction costs, under pressure from the developers.

Even after Aneha's sworn testimony and Huser's notification to residents that the building was not safe, the Ota government claimed it could not confirm that the building was not up to code, which has lead to the current strength check.

The ward government certified the building plans, submitted by Huser.

Investigators will also drill into the building frame.