Pretty hard to show that "I don't remember" is a lie. Hillary has gotten away with that line for years.
That's right, but I recently read somewhere the DOJ was prosecuting someone for just that, lying, when the individual said they could not recall the facts (I don't recall where I saw this).
Even if the evidence of lying is thin, I think that the saying that "the process is the punishment" comes into play here. Maybe she can't recall, but prosecute her anyway and drain her money.