"Barr said the investigation also found insufficient evidence that Trump had attempted to obstruct justice. Many of his opponents accused him of obstructing the Russia probe when he fired former FBI director James Comey."
Mueller report does not have proof of Trump crimes -Justice Department
Poor LL
It was Barr's decision, not Mueller's, that Trump did not obstruct justice. Mueller laid out evidence on both sides. So it was Barr who found not enough evidence to prosecute.
After making a "thorough factual investigation" into these matters, the Special Counsel considered whether to evaluate the conduct under Department standards governing prosecution and declination decisions but ultimately determined not to make a traditional prosecutorial judgment. The Special Counsel therefore did not draw a conclusion -- one way or the other – as to whether the examined conducted constituted obstruction. Instead, for each of the relevant actions investigated , the report sets out evidence on both sides of the question and leaves unresolved what the Special Counsel views as "difficult issues" of law and fact concerning whether the President's actions and intent could be viewed as obstruction. The Special Counsel states that "while this report does not conclude that the President committed a crime, it also does not exonerate him."
The AG goes on to explain that since Mueller did not come to any legal conclusions on this,
it is up to Barr himself to determine whether there was a crime. He determined there was not.
AG Barr quotes Mueller as saying "the evidence does not establish that the President wa involved in an underlying crime related to Russian election interference."
Read: Justice Department summary of Mueller report - CNNPolitics