On May 11, Trump admits he Fired Comey over Russia investigation. President Trump admitted this to Lester Holt. 7 days later, Rosenstein appoints Mueller. Later, when Comey is asked by Congress if Trump fired him over Russia, Comey said, “I take [Trump] at his word.” This is evidence of the obstruction of justice crime.
Verified: Not in dispute. Trump did this on national television.