In the end, that's all up to the investigator, but there isn't a strict guideline other than something that could be used against a subject of blackmail for information.P>
Every single person in government at all levels, state, city, county, and federal should be investigated independently, on an on going basis, this would include financial, criminal, and background investigations, random drug testing etc, from congress down to the government public school teachers. All communications between them, outside of those directly involved in national security issues should be recorded and documented daily.
The government has proved over and over and over, it can not be trusted.
Reforms and oversight of government employees are desperately needed, in addition to a reduction of their wages and benefits and pensions.
These reforms must occur, while at the same time, millions of government positions must be eliminated, as these government employees have become a crushing burden on the American tax payer.
Look at these high government officials and these government departments jammed with incompetent, corrupt, over paid, and extremely questionable individuals...
Remember not long ago when foreigners that were in this country illegally, were found wandering around the inside of Bush's Homeland Security Chief's private residence? During wartime yet.