The Office of Congressional Ethics revealed Tuesday that it opened 21 inquiries in the second quarter of 2010 but terminated nearly one-third of those matters after a preliminary review.

According to its quarterly report, the OCE, which reviews potential rules violations and recommends investigations to the House ethics committee, has initiated 69 investigations to date in the 111th Congress.

Assuming those investigations did not target the same Member more than once, that figure represents nearly 16 percent of the House’s membership.

The OCE does not publicly discuss its investigations and does not provide details of its reviews in the quarterly report, only statistical information.

Among the 21 inquiries it initiated since April 2010, six were terminated during the initial 30-day review period. Another 14 have reached the second phase of review, meaning they will ultimately be referred to the ethics committee for investigation or dismissal.

The report also indicates that at least one Member under review as of May 14 resigned from the House by June 30, while the investigation was still under way. The only Member to resign during the period is Rep. Mark Souder (R-Ind.), who stepped down May 18 after revealing an affair with one of his aides.

The OCE declined to confirm Souder’s identity, and a telephone number listed for Souder in Fort Wayne, Ind., has been disconnected.

Among the inquiries still under review as of late June, eight lawmakers — Reps. John Campbell (R-Calif.), Frank Lucas (R-Okla.), Chris Lee (R-N.Y.), Joe Crowley (D-N.Y.), Jeb Hensarling (R-Texas), Mel Watt (D-N.C.), Tom Price (R-Ga.) and Earl Pomeroy (D-N.D.) — are being probed over fundraising or fundraisers held immediately before the 2009 financial reform vote.

The quasi-independent OCE, established by House lawmakers in 2008 in an effort to increase transparency in the ethics process, reported it has referred 25 matters — 12 for further review, and 13 recommendations to dismiss — to the ethics committee in the 111th Congress.

The OCE conducts its investigations in two stages: a 30-day preliminary review and a second phase of up to 59 days. If the OCE dismisses an inquiry after the preliminary stage, its report it not made public. However, if the OCE refers a matter to the ethics committee for further review, that report must eventually be released to the public.

Should the OCE refer a matter to the ethics panel but recommend an investigation be dismissed, however, the ethics committee is not required to release that report.