The partially built State Audit Office was the only building to collapse in the Thai capital during a 7.7 magnitude earthquake in March.

A total of 92 bodies have been recovered from the site of the collapsed 30-storey building during a six-week operation while four remained missing.

Premchai Karnasuta, president of Italian Thai Development and the 14 other suspects were affiliated with companies responsible for building design and construction, said Metropolitan Police Bureau deputy commissioner Noppasin Poonsawat. They have been accused of negligence and breaching construction regulations.

Noppasin said, 鈥淓xpert assessments revealed that the architectural design did not comply with ministerial regulations or meet the technical standards outlined in the terms of reference.鈥�

There were also irregularities in construction materials used, including substandard concrete and steel, adding that investigators also discovered forged signatures in engineering documents.

A watchdog organisation flagged days after the quake that corruption may have been involved in the building鈥檚 construction. Initial tests of materials gathered at the site in March indicated the presence of substandard steel among the wreckage structure, according to industry ministry officials.

The 15 suspects have been brought to court for pre-trial proceedings and have denied all charges, while two additional suspects would report to authorities on Monday.

An investigation was still underway over the causes of the collapse, one of the country鈥檚 deadliest.

Italian Thai Development has said it is cooperating with authorities.