The House Ethics Committee said Monday it is conducting a preliminary probe of two Democratic Congressmen and a top Democratic House aide.

Rep. John Conyers, D-Mich., the Dean of the House, faces scrutiny as does Rep. Ben Ray Luján, D-Calif. Luján is a top lieutenant to House Minority Leader Nancy Pelosi, D-Calif., and chairs the Democratic Congressional Campaign Committee. Also named in the probe is Michael Collins, chief of staff to Rep. John Lewis, D-Ga.

While the Ethics Committee is looking at the trio at the behest of the Office of Congressional Ethics, it’s not clear what the committee is evaluating with all three.

A spokesman for Luján told the Washington Post the investigation is linked to a complaint filed by a conservative watchdog group last year about the sit-in led by Democrats on the House floor in response to the Orlando nightclub massacre. The Foundation for Accountability and Civic Trust at the time said Luján improperly used images of Democrats on the House floor in fundraising emails.

The Ethics Committee has not empaneled an “investigative subcommittee,” the equivalent of a Congressional “indictment” in the ethics world, and says it will resolve the issues by August 9.

Fox News’ Chad Pergram contributed to this report.