[jasode]

>You can be just as evasive in the active voice. Someone made a mistake.

Yes, but by explicitly adding the word "someone [...]", the hiding/concealment is calling attention to itself. It's an unusual and awkward construction of a sentence -- or -- the writer was trying to write a mystery/crime novel.

On the other hand, if the writer doesn't want to name the agent without drawing attention to the writing style, the overuse of passive "to be" verbs instead of active verbs is the way to do it. Passive voice is the hallmark of government bureaucratic reports and they're boring and lack punch.

>Most uses of the passive have nothing to do with being evasive.

I agree.