The U.S. government wiretapped former Trump campaign chairman Paul Manafort before and after the presidential election, CNN is reporting.

According to the bombshell report, the surveillance, which was granted under the Foreign Intelligence Surveillance Act, continued into early this year.

U.S. investigators first obtained a secret order to conduct surveillance on Manafort after he became the subject of an FBI investigation in 2014 because of his consulting work for a Ukrainian political party.

The surveillance was ended at some point last year because of a lack of evidence, one source told CNN, but investigators obtained another warrant at some point during the presidential campaign.

It is not clear exactly when the second surveillance warrant was obtained, though it was after the now-infamous meeting held at Trump Tower last June. Manafort attended the meeting along with Donald Trump Jr., Jared Kushner and a group of Russians with alleged ties to the Russian government.

Manafort was picked as Trump’s campaign chairman last May. He lasted through August, when he was essentially fired over revelations about his consulting work in Ukraine.

According to CNN, the FBI became more interested in Manafort during the fall after intercepting communications between the longtime GOP lobbyist and Russian operatives.

The wiretap on Manafort has yielded intelligence of interest to Special Counsel Robert Mueller, who is overseeing the investigation into Russian meddling in the presidential campaign.

Mueller obtained a search warrant of Manafort’s Virginia residence in late July. Federal agents also conducted a search of a storage facility that belongs to Manafort, according to CNN. The latter search appears to have been carried out earlier this year, before Mueller took over the Russia investigation.

It is unclear if the surveillance captured conversations between Manafort and Trump. The two have reportedly spoken since Trump took office.