From CNN
Washington (CNN)US investigators wiretapped former Trump campaign chairman Paul Manafort under secret court orders before and after the election, sources tell CNN, an extraordinary step involving a high-ranking campaign official now at the center of the Russia meddling probe.
The government snooping continued into early this year, including a period when Manafort was known to talk to President Donald Trump.
And:
Manafort was ousted from the campaign in August. By then the FBI had noticed what counterintelligence agents thought was a series of odd connections between Trump associates and Russia. The CIA also had developed information, including from human intelligence sources, that they believed showed Russian President Vladimir Putin had ordered his intelligence services to conduct a broad operation to meddle with the US election, according to current and former US officials
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The FBI surveillance teams, under a new FISA warrant, began monitoring Manafort again, sources tell CNN.