"Campaign refused to cooperate with (FBI) investigation..."

"Russians 'likely responsible' for Clinton campaign hack"

The Justice Department’s national-security division is investigating the cyber attacks. The FBI warned the Clinton campaign in March that it had been targeted by hackers, Yahoo News said.

But the campaign refused to cooperate with the investigation — holding back data the FBI had requested to look into the matter, Yahoo reported.

The Clinton campaign believed the request would have meant turning over too much sensitive information to the FBI, which at the time was also in the middle of a separate lengthy investigation into Clinton’s use of a private ­e-mail server while she served as secretary of state.

The Clinton campaign downplayed the severity of the latest hacking, maintaining it was confined to “an analytics data program maintained by the DNC, and used by our campaign and a number of other entities,” spokesman Nick Merrill said.

“Our campaign computer system has been under review by outside cybersecurity experts,” he said. “To date, they have found no evidence that our internal systems have been compromised.”