Code Name Crossfire Hurricane: The Secret Origins of the Trump Investigation
By Matt Apuzzo, Adam Goldman and Nicholas Fandos | May 16, 2018~snip~
The F.B.I. investigated four unidentified Trump campaign aides in those early months, congressional investigators revealed in February. The four men were Michael T. Flynn, Paul Manafort, Carter Page and Mr. Papadopoulos, current and former officials said. Each was scrutinized because of his obvious or suspected Russian ties.
~snip
The F.B.I. obtained phone records and other documents using national security letters — a secret type of subpoena — officials said. And at least one government informant met several times with Mr. Page and Mr. Papadopoulos, current and former officials said. That has become a politically contentious point, with Mr. Trump’s allies questioning whether the F.B.I. was spying on the Trump campaign or trying to entrap campaign officials.
~snip~
But officials have told the inspector general something quite different. They said Ms. Page and others advocated a slower, circumspect pace, especially because polls predicted Mr. Trump’s defeat. They said that anything the F.B.I. did publicly would only give fodder to Mr. Trump’s claims on the campaign trail that the election was rigged.
Mr. Strzok countered that even if Mr. Trump’s chances of victory were low — like dying before 40 — the stakes were too high to justify inaction.
https://www.nytimes.com/2018/05/16/us/politics/crossfire-hurricane-trump-russia-fbi-mueller-investigation.html
The NY Times certainly indicates that it was spying, especially considering how Strzok urged to press forward with the 'investigation' (including surveillance) while the campaign was still ongoing instead of waiting until after it was over.