Donald Trump fired FBI Director James Comey while placing the responsibility for the decision on the opinions of Attorney General Jeff Sessions and deputy Attorney General Rod Rosenstein. He additionally initially it was due to a poor opinion in the FBI of Comey’s performance. After bipartisan push back, he reversed and said the decision was his own and he had decided the Russian probe was a “fake news” story. Within another day he went back to shifting blame to Rosenstein’s letter.
James Comey had been investigating contacts between Trump’s campaign and transition staff and Russian government officials when he was fired.
https://www.nytimes.com/2017/05/09/us/politics/james-comey-fired-fbi.html?_r=0