Since there was a movement of funds from the original 401(k), there was a distribution that is reportable on Form 1099-R and reportable on your tax return.
It's not clear whether the funds actually made it into another qualified retirement account. If the funds actually made it into another qualified retirement account and were subsequently stolen, the distribution from the original 401(k) is reportable as a rollover. If the funds never made it to another qualified retirement account, it's reportable as an ordinary distribution from the original 401(k).
