An easy excuse to not look into the potential ethics violations of a Democratic leader or a clerical error?

The conservative watchdog group Cause of Action says the Senate Ethics Committee is claiming to have misplaced an ethics complaint about Sen. Harry Reid (D-NV) sent over 300 days ago — and that the committee acknowledge receiving at the time.

“It is a little mysterious that we have a return receipt from the Senate mail and they say they never received it. That’s a comfortable excuse for not investigating something,” Dan Epstein, the Executive Director of Cause of Action, said in an interview with Breitbart News Tuesday.

On December 16, 2013 Cause of Action submitted an ethics complaint charging that Reid inappropriately influenced then-U.S. Citizenship and Immigration Services (USCIS) Director Alejandro Mayorkas and another official for the approval of EB-5 visas for certain “favored investors” that had not been approved due to “suspicious financial activity.”

“Despite the fact that these applications were ineligible for appeal, Senator Reid’s efforts to lobby USCIS resulted in the reconsideration and approval of these applications, as well as the subsequent securing of millions of dollars in foreign and domestic funds for the SLS Hotel & Casino and American Dream Fund EB-5 Regional Center- both of which are major contributors to the Democratic Party and its candidates,” the initial December complain letter read. “Even more troublesome is the fact that Senator Reid’s son, Rory Reid, and his law firm, Lionel, Sawyer & Collins P.C., are legal counsel to the SLS Hotel & Casino.”

According to Cause of Action, despite receiving a receipt that the committee received the complaint, traffic statistics showing Senate visits to the complaint on Cause of Action’s website, and press reports about the complaint, the Committee’s Chief Counsel and Staff Director John C. Sassaman, told Cause of Action on Oct. 22 that the Committee “never received” the complaint.

Epstein said that while he takes Sassaman at his word that the Committee never received the complaint, the explanation is convenient as there is evidence that the committee did know about the complaint.

“It’s clear they knew of this complaint. They had every opportunity to contact us if they didn’t receive the complaint,” he said.

As to why the alleged misconduct would have gone un-investigated, Epstein theorized that is could be because it dealt with Reid, the Senate Majority Leader.

“My only thought and this is purely speculative is that they looked for a comfortable excuse not to look into these issues, and they are important issues. We raise very serious allegations about whether Sen. Harry Reid was inappropriately inserting himself into the USCIS process for approving EB-5 visas and if that was true this guy should be investigated and properly reprimanded,” he said.

Last week Cause of Action re-submitted its complaint to the Ethics Committee, along with a letter expressing some incredulity that the initial complaint was ever actually lost.

“Given Mr. Sassaman’s call and the Committee’s record of inaction, the public certainly has reason to be concerned about the integrity and thoroughness of Committee review in this case. Nevertheless, Cause of Action trusts that the Committee will act promptly and in good faith with respect to this matter,” Epstein wrote in the most recent letter to the committee.