Two weeks before his inauguration, Donald J. Trump was shown highly classified intelligence indicating that President Vladimir V. Putin of Russia had personally ordered complex cyberattacks to sway the 2016 American election.
The evidence included texts and emails from Russian military officers and information gleaned from a top-secret source close to Mr. Putin, who had described to the C.I.A. how the Kremlin decided to execute its campaign of hacking and disinformation.