(CNN) -- Here are highlights of the Justice Department inspector general's report on "Operation Fast and Furious," the botched gun-trafficking probe that allowed hundreds of guns to reach Mexican drug cartels:
-- "While we found no evidence that the agents responsible for the cases had improper motives or were trying to accomplish anything other than dismantling a dangerous firearms trafficking organization, we concluded that the conduct and supervision of the investigations was significantly flawed."
-- Officials from the Bureau of Alcohol, Tobacco, Firearms and Explosives and the U.S. attorney's office in Phoenix "provided demonstrably inaccurate and conflicting information" to Justice Department officials as they drafted a later-retracted response to questions from Sen. Charles Grassley about the probe. However, the report adds, "the Department is ultimately responsible for representations that it makes to Congress."
-- Attorney General Eric Holder "did not learn about Operation Fast and Furious until late January or early February 2011 and was not aware of allegations of 'gun walking' in the investigation until February." Though Justice Department divisions send weekly reports to the attorney general's office, "We determined that these reports did not refer to agents' failure to interdict firearms or include information that otherwise provided notice of the improper strategy and tactics that ATF agents were using in the investigation."
-- Kenneth Melson, the former acting ATF director whose retirement was announced Wednesday, "was not well served" by his subordinates. However, as an experienced prosecutor, Melson "should have asked basic questions about the investigation, including how public safety was being protected." And after developing concerns about the probe in 2010, he failed to warn Holder's top aides and "lacked sufficient urgency" about the issue.
-- Holder's acting deputy and current chief of staff, Gary Grindler, was told of the link between Fast and Furious and the killing of Border Patrol Agent Brian Terry in December 2010, and "should have informed the Attorney General as well as made an appropriate inquiry of ATF or the U.S. Attorney's Office about the connection."
-- Deputy Assistant Attorney General Jason Weinstein, who resigned when the report was released, "was the most senior person in the Department in April and May 2010 who was in a position to identify the similarity between the inappropriate tactics used in Operations Wide Receiver and Fast and Furious." Notes from an April 2010 meeting about the earlier operation show Weinstein "did not admonish ATF," and the meeting "focused instead on how to avoid negative press."
-- Criminal Division chief Lanny Breuer failed to warn Holder or his deputy about concerns about Operation Wide Receiver, a 2006-2007 gun probe that used similar tactics, when he learned about them in April 2010. Breuer admitted that in testimony to Congress in November.
-- Dennis Burke, the U.S. attorney in Phoenix, "failed to exercise responsible oversight and failed to provide the leadership and judgment required of a United States attorney." Burke resigned in 2011, as investigations into the probe gathered steam.