Supporters of mass surveillance provisions in the Patriot Act insist such measures are critical to keeping the nation safe, but a new report from the Justice Department's inspector general found that the FBI can't identify a single major terrorism case development that resulted from use of those spying powers.

"The agents we interviewed did not identify any major case developments that resulted from use of the records obtained in response to Section 215 orders," Inspector General Michael Horowitz wrote. Agents did, however, believe the data they collected was "valuable" in developing other leads and corroborating information, Horowitz added.

Section 215 of the Patriot Act allows the FBI to collect various business records, such as medical, educational or tax information, along with other "tangible things" related to an ongoing counter-terrorism or espionage investigation, according to The Guardian. The National Security Agency also uses the section as legal basis for its bulk collection of millions of Americans' phone metadata, which a federal appeals court ruled illegal earlier this month.

It turns out, according to the inspector general's report, that between 2004 and 2009, the FBI tripled its bulk collection of business-related data, increasingly scooping up records of Americans who had no ties to ongoing terrorism investigations. The report said the bureau began using its business-related authority to "obtain large collections of metadata," such as "electronic communication transactional information."

Much of the report is redacted, but The Guardian noted that electronic communication transactional information likely refers to records of email, instant messages, texts and maybe even Internet Protocl addresses.

While the FBI did eventually establish procedures to attempt to minimize the collection of data from Americans not under investigation - five years later - Horowitz said in his 77-page report that the process took far too long.

"It's an indictment of the system of oversight that we've relied upon to check abuses of surveillance powers. The report makes clear that, for years, the FBI failed to comply with its basic legal requirements in using Section 215, and that should trouble anyone who thinks that secret oversight is enough for surveillance capabilities that are this powerful," Alex Abdo, a staff attorney at the American Civil Liberties Union, told The Huffington Post.

The Section 215 provision is set to expire on June 1 unless reauthorized by Congress, who is divided on how to move forward, with the Senate expected to vote in the next couple days on expiring sections.

Some establishment lawmakers, such as Senate Majority Leader Mitch McConnell, R-Ky., would like to see the Patriot Act remain as is, as they believe anything less would jeopardize national security.

Others, including the Obama administration, are pushing for a reform measure known as the USA Freedom Act, which would allegedly stop bulk collection of phone data while preserving the rest of Section 215. That measure passed the House last week in a 338-88 vote.

And then a final group, including at least 60 House members, a few senators, and a number of privacy and civil liberty groups, say both options are detrimental to the privacy of Americans and would like to see the entire Section 215 removed rather than just the bulk collection provision.

The latest inspector general report seems to add credibility to the latter's argument, casting doubt as to whether the spying provisions have actually thwarted any terrorist attacks.

"This report adds to the mounting evidence that Section 215 has done little to protect Americans and should be put to rest," Abdo said, according to The Guardian. "As Congress debates whether to rein in the NSA, this investigation underscores how sweeping the government's surveillance programs are and how essential systemic reform is right now."