When will ACORN and those responsible for voter fraud be prosecuted, and expose Obama's role?

What's the process after an FBI office raid? How long does that mean law enforcement knew there was voter fraud. In Nevada the head of the voter registration office said half of the ACORN cards were fraudulent at first glance, ie. many signed in same writing, phoney names, addresses, phone numbers, etc. How many more will be found to be improper once more are scrutinized. She said they didn't have the time to fully look into and try to verify them all.