We know Hal Finney was involved with Bitcoin in the early days and we know he died. I think Satoshi and Finney worked together on Bitcoin and when Finney died and Gavin was approached by the government, Satoshi got spooked. The private keys for those coins was recorded, but it was worth a few pennies and they did not bother to keep it, because it was seen as part of a experiment.

The Satoshi millions are lost forever ^smile^