His investigative board kept discovering that his prospective appointees were corrupt in any of several uninteresting ways.

He was going to have to get rid of the investigative board.

The investigative board has not set up an office to handle questions, and for the time being the regular daily briefings have been curtailed.

An investigative board will be convened at once, they said.

They're pulling together the investigative board now.

The investigative board has now picked up that line of inquiry.

The investigative board may now focus new light on these devices.

According to Antoni Macierewicz, a member of the investigative board:

Just as important, the investigative board determined, a "broken safety culture" tended to play down risks.

But there could also be other explanations, and the issue is being turned over to an investigative board.