The Office of Congressional Ethics did not open a single new investigation in the last half of 2010, according to a report the office released Monday.

The OCE, which is tasked with reviewing potential rules violations and referring matters to the House Ethics Committee, detailed its work in a quarterly report.

The report, covering the fourth quarter of 2010, provides statistics on the office’s work but does not identify the Members or specific allegations reviewed by the office.

There is no explanation for why the OCE did not initiate any new investigations between July and December, although the office did refer two of its pending cases to the Ethics Committee. It recommended the Ethics Committee investigate one of those matters and dismiss the other without action.

The OCE is prohibited from forwarding cases to the Ethics Committee in the 60 days before an election in which a Member is a candidate, which could account for some of the drop off in activity at the OCE in the last half of the year.

According to the report, the OCE initiated a total of 69 reviews in the 111th Congress. It began conducting investigations in early 2009.

The OCE issued 40 referrals to the Ethics Committee, including 22 cases in which it recommended the House panel pursue its own investigation. It recommended no action in the remaining 18 cases.

The OCE also reported that it closed 28 cases, or nearly 41 percent of those matters, after a “preliminary review.”

Unlike those cases in which the OCE recommends further review, there is no public disclosure requirement when the office closes an investigation after its initial stage.

The report also indicates that about 2,600 private citizens contacted the OCE during its first Congressional cycle. The report does not distinguish between individuals seeking information on the OCE and those who recommended investigations to the office.

The OCE report notes that about 1,700 of those individuals contacted the office about “a single issue involving the Executive Branch.” The OCE does not disclose the subject of those calls, although the incidents occurred following a statement by then-Rep. Joe Sestak (D-Pa.) that he had been offered a post in the Obama administration to avoid a primary challenge to then-Sen. Arlen Specter (D).