Stanford’s CFO, who has also been charged along with Sir Allen in the Ponzi scheme, will be cooperating with authorities, according to the FT.
It’s been a while (and there’s been a Supreme Court decision) since I really understood how sentencing of cooperators works in US federal courts. If I remember correctly, the CFO will plead guilty to charges that get him the worst possible sentence he could get. After he has cooperated with the government but before he is sentenced, the government will file a 5K motion for a downward departure from the mandatory minimum sentencing guidelines. A cooperator can go from a mandatory life sentence to a year or even less. For a while there, judges could not give a sentence below the mandatory minimums without a 5K. This shifted a lot of the power for sentencing to the prosecutors. For a cooperator, it can be a lot of pressure to say what you think the prosecutor wants to hear.
If all goes right, the prosecutor will have the right incentives to get the cooperator to tell the truth and not say what conveniently fits in with the rest of the case. I’m guessing that in this particular case there is probably a fairly decent paper trail to corroborate anything the CFO has to say.