I have had this happen to me in sept 2010 origionated in chigago after CanJam which I attended.
I had gotten a call from american express asking me if I had called requesting a $500 cash advance because visiting someone and the house burned down.
They had all my info social # mothers maiden name even password. Amex cancelled my card and overnighted a new one to me, who ever did this was into the new card before I even received it, & this happened 3 times in the next 2 weeks. The security so called experts couldn't figure out how it was being done.After the fifth expert they finally figured it that it was from a online amex account I had bought advance sale tickets using my amex card
They also moved $ 2500 from my business checking account to my personal card to access more cash.
They also tried to change my address & contact info on my Visa card & applied for a gas credit card.
I went through 2 weeks of hell dealing with the on going tries of the identity people.
I had to close all my checking & savings accounts personal & business,Canceled all my credit cards & got new ones. I froze my credit reports with the credit bureaus right a way to stop any more tries which was many, I must of spent 4-5hrs a day dealing with this over a 2 week time frame.
You must contact the 3 credit agencys, I filed reports with the FTC,FBI and local police .
I have a credit alert service protect my ID .com that charges a monthly fee and notifies me by email,text if any inquires or cahnges have been tried to my accounts
MY credit reports are still frozen & if I need to apply for credit I have to unfreeze the reports so my credit can be checked,then refreeze them after.
I caught it early on thanks to the phone call from amex the first day & limited the damages & now have checks in place to help prevent it.
Good luck, It was hell dealing with this.