The U.S. government, under a Foreign Intelligence Surveillance Court order, wiretapped Paul Manafort, the former Trump campaign manager whose dealings in Ukraine led to him becoming a central figure in the investigation of Russia inference in the U.S. presidential campaign.
Suspicious of his work on behalf of Ukraine’s ruling party, investigators  first obtained a FISA court order to tap Manafort in 2014, according to a report by CNN. 

After a brief respite in 2016, when the probe failed to yield compelling evidence of wrongdoing, the government obtained a second order later that year to conduct surveillance with the express purpose of probing potential collusion between members of the Trump campaign and Russian operatives, CNN reported. The surveillance included a time when Manafort was having conversations with Trump that extended long beyond his employment by the campaign – Manafort was pushed out of his position as campaign manager in August 2016.

“This means a federal judge reviewed evidence & concluded there was probable cause Manafort engaged in crimes or was agent of foreign power,” Rep. Ted Lieu, D-Calif., tweeted.