Last month, I looked at how Siemens was struggling to change its bribe-prone culture. At the time, I said it would take more than a new chief executive to root out the corrupt practices inside the company's systems.

Now we have proof of that with The Wall Street Journal reporting that German prosecutors have broadened their bribery investigation to include the power transmission business and warning that other units of Siemens, which makes everything from AC converters and geared motors, to packaging and light bulbs, could be caught in the net.

The problem for Siemens is that this could complicate any settlement with the Securities and Exchange Commission and the Department of Justice, which are probing Siemens under the Foreign Corrupt Practices Act.

Clearly this problem is not going away. And one very good reason is that the company's management had known there was a bribery problem for many years, and had done nothing about it. Deutsche Welle reports that the company's former management board knew about the bribery allegations as far back as 2003 and other reports that it was involved in spying.