American TV network CBS News reported that the search was on to discover either a CIA employee or a contractor who had had access to the Vault 7 documents.
The news appears to confirm WikiLeaks' claims that the documents released are genuine CIA material.
According to CBS' sources, the Vault 7 documents were classified and stored securely but hundreds would have had access and a list of names was being examined to try and find the alleged culprit.
"It is time to call out WikiLeaks for what it really is: A non-state hostile intelligence service often abetted by state actors like Russia," he said.
WikiLeaks has not identified the source of the documents, but only said that it was not from a state-level actor.