Pfeiffer said the private contact information of the Republican members of Congress was obtained by a group known as "AnonOps." Pfeiffer said he did not know how the information was obtained, whether it was a leak or an online hack. He said some of the cellphone numbers, for example, had been verified as real. Among the politicians on the list were U.S. Sens. Ben Sasse of Nebraska, Bob Corker of Tennessee and Charles Grassley of Iowa.