There is no evidence that Attorney General Eric Holder and high-ranking officials at the Justice Department knew that guns were allowed to “walk” during an ATF operation known as Fast and Furious, according to a report released on Wednesday afternoon by the department’s internal watchdog.

Following a 19-month investigation, the Inspector General found that the decision not to take action against low-level “straw purchasers” was made by the Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF) and the Arizona U.S. Attorney’s office. Their decision, according to the report, “was primarily the result of tactical and strategic decisions by the agents and prosecutors, rather than because of any legal limitation on their ability to do so.” Dennis Burke, the head of the U.S. Attorney’s office at the time, resigned from his position in August 2011.

The IG report is considered to be the most comprehensive and least partisan account of the scandal available to date. Unlike investigators with Rep. Darrell Issa’s House Oversight Committee, DOJ investigators had access to criminal investigation files.

Fast and Furious was the Arizona component of a broader effort to combat gun trafficking known as Project Gunrunner, which had previously come under fire from the Inspector General for failing to net “higher-level traffickers, smugglers, and the ultimate recipients of the trafficked guns.” Instead of going after the straw purchasers during Fast and Furious, ATF investigators allegedly made an effort to find the kingpins of the operation and deal a bigger blow to the trafficking network. But in doing so, agents lost track of many of the weapons, allowing them to flow into the hands of criminals on both sides of the border. One of the weapons connected to the investigation was found at the scene of Border Patrol Agent Brian Terry’s murder in December 2010.