1) You can set Instant Messaging software to save IMs indefinitely, AOL has a 14-day default, but Trillian and other programs save them forever unless you turn off the feature.
2) The Feds will subpoena everything sent from Foley's AOL account, be it emails or instant messages....and there could be even more young men out there that havent involved themselves in this episode at this time.
Has there even been a crime? What crime are they investigating?