Fox News‘ Catherine Herridge reports today that DOJ Inspector General Michael Horowitz will release his long-awaited report on the FBI’s handling of the Clinton email investigation in May.

Horowitz addressed the timing in a letter to Senator Judiciary Committee Chairman Chuck Grassley, R-Iowa.

He wrote that the report, which began in January 2017 with bipartisan support, has been extended due to “potentially important additional information and documents that recently came to our attention, and the interviews they have required us to conduct.” Horowitz continued, “my expectation is that we will issue our report in May, absent any new developments.”…

The IG is thought to be looking at everything from political bias to how evidence was handled in the Clinton email case. Information has continued to emerge in recent months relevant to that case.

So what’s going to be in this report? The IG has been very tight-lipped but a report published in January by the Washington Post indicated Horowitz was looking at McCabe’s apparent failure to pursue a probe involving Hillary’s email server:

The Justice Department’s inspector general has been focused for months on why Andrew McCabe, as the No. 2 official at the FBI, appeared not to act for about three weeks on a request to examine a batch of Hillary Clinton-related emails found in the latter stages of the 2016 election campaign, according to people familiar with the matter.

The inspector general, Michael E. Horowitz, has been asking witnesses why FBI leadership seemed unwilling to move forward on the examination of emails found on the laptop of former congressman Anthony Weiner (D-N.Y.) until late October — about three weeks after first being alerted to the issue, according to these people, who spoke on the condition of anonymity to discuss the sensitive matter.

A key question of the internal investigation is whether McCabe or anyone else at the FBI wanted to avoid taking action on the laptop findings until after the Nov. 8 election, these people said. It is unclear whether the inspector general has reached any conclusions on that point.

Horowitz was also looking into why an investigation into the Clinton Foundation also seemed to stall at McCabe’s desk:

At the same time, the FBI was facing a new set of questions, this time about McCabe’s role in a stalled probe into the Clinton Foundation. Some within the FBI felt McCabe had repeatedly moved to hamstring that probe and were suspicious of his motives for doing so, according to people familiar with the matter.

It was a report about McCabe’s possible lack of impartiality which led him to leak information to the Wall Street Journal. IG Horowitz released a report last week which showed conclusively that McCabe had lied under oath to FBI investigators about having approved those leaks. According to that report, a WSJ reporter had information claiming McCabe had issued a stand-down order related to the Clinton Foundation probe. McCabe wanted to rebut that story by showing that he had fought (on the phone) to keep the Clinton probe open. The leak effectively confirmed that an investigation into the Clinton Foundation was underway, information seen as harmful to Clinton.

Do the leaks prove that McCabe was not seeking to help Clinton by slow-walking investigations behind the scenes? Or do they just prove he wanted to a) defend himself and b) avoid being pegged as Clinton’s defender and potentially being forced to recuse himself from any investigations involving her? McCabe’s impartiality is one of the big questions the IG report will hopefully sort out when it is released next month.