Sunday on ABC’s “This Week,” ABC News Chief White House Correspondent Jonathan Karl reported that it’s “highly likely” that a full backup of Hillary Clinton’s private email server was made.

Karl said, “Out in Iowa this weekend, Hillary Clinton joked about the thousands of emails she deleted from her time as secretary of state. … But her infamous private server is now in the hands of the FBI, which is intensifying its investigation into the handling of classified information in her emails. According to sources familiar with the investigation, it’s already been determined that at least two of the emails included information that is top secret. Some of it from so-called signals intelligence, among the most sensitive intelligence there is. Investigators are also trying to determine if the Chinese or Russians were able to get access to Clinton’s private emails.”

He continued, “But, in the most intriguing new development, Platte River Networks, the Colorado company that set up Clinton’s server, told ABC News it is highly likely that a full backup of the server was made, meaning those thousands of emails she deleted, may still exist. The company says it’s cooperating with the FBI.”

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