U.S. Monitored Manafort After He Left Trump Campaign
The surveillance came as part of a counterintelligence probe into Russian interference with presidential election
U.S. authorities placed Paul Manafort under surveillance after he was ousted as Donald Trump’s campaign manager in the summer of 2016, according to U.S. officials with knowledge of the matter.
The surveillance, which was part of a counterintelligence investigation into Russian interference with the presidential election, didn’t involve listening to Mr. Manafort’s phone communications in real-time, the officials said.
Let's note that "not listening in real-time" doesn't mean they weren't recording and replaying his phone calls.
But armed with a warrant, investigators still could have conducted clandestine surveillance of Mr. Manafort, possibly by obtaining copies of his emails and other electronically stored communications, or by having agents follow him or conduct physical searches of his property.
The surveillance began after Mr. Manafort left the Trump campaign in August, but it is not clear when it was suspended. Mr. Manafort resigned after a spate of publicity about his consulting work in Ukraine on behalf of Russian President Vladimir Putin’s allies.
None of which resolves whether there were serious concerns about Manafort or he was simply the closest person to Trump for whom the FBI could plausibly argue for a warrant.