If their investigation proved fruitless, they were to be allowed to return to California.

A quick investigation with flashlights would have proven that someone was near by.

But until a thorough investigation proved that, he would be under some degree of suspicion, even though his story made sense.

Or if he does suspect, investigation will prove that he's wrong.

And if a subsequent investigation proved that Lee wasn't responsible?

But our investigation could not prove that he had done anything wrong, so we cleared him.

"For your sake, I hope an investigation proves you right."

Certainly not the nuclear industry who would have too much to lose if the investigation proved that the health risks are high.

A forensic investigation later proved the testament to be real.

But the investigation proved draining, and he died of a stroke in 1950.