On September 20, 2012, just nine days after the terrorist attacks on the U.S. diplomatic facility in Benghazi, Libya, the House Government Oversight Committee sent a letter to Secretary of State Hillary Clinton requesting that she turn over "all information … related to the attack on the consulate."

About two weeks later, on October 2, 2012, Clinton responded, saying she would cooperate fully with the investigation into what went wrong in Benghazi.

"We look forward to working with Congress and your committee as you proceed with your own review," Clinton told committee chairman Rep. Darrell Issa. "We are committed to a process that is as transparent as possible, respecting the needs and integrity of the investigations underway. We will move as quickly as we can without forsaking accuracy."

We now know that that statement was not true. We know because Hillary Clinton herself told us.

Beginning with that September 20, 2012 letter, House investigators made repeated appeals to the State Department for documents and information on Benghazi. After much haggling and legal maneuvering, State turned over a significant amount of material. Officials there not only pledged cooperation but told the House that they had turned over all the documents requested.

"The State Department actively told us that they were cooperating with us," recalls one knowledgeable Hill Republican. "They made representations that the documents [turned over] were complete and responsive."

Yet when Clinton's secret email system was exposed this year, she turned over about 850 never-before-seen pages of Benghazi-related documents to the State Department, which in turn gave them to the House. Those documents had been under a request from Congress since the September 20, 2012 letter. The former secretary of state let more than two years pass before producing the information.

Take Clinton at her word that she turned over everything on her secret system related to Benghazi. The 850 pages still show that she withheld information from Congress for more than two years.

Concealing information from Congress is not a minor offense. The law allows for fines and punishment of up to several years in jail for anyone found guilty of doing it. Three examples:

1) 18 U.S. Code 1001 states that anyone who "falsifies, conceals, or covers up by any trick, scheme, or device a material fact" in the course of "any investigation or review, conducted pursuant to the authority of any committee, subcommittee, commission or office of the Congress" could face a prison sentence of up to eight years.

2) 18 U.S. Code 1505 says that anyone who "obstructs, or impedes or endeavors to influence, obstruct, or impede…the due and proper exercise of the power of inquiry under which any inquiry or investigation is being had by either House, or any committee of either House, or any joint committee of the Congress" could face a five-year prison term.

3) 18 U.S. Code 1519 states that anyone who "knowingly alters, destroys, mutilates, conceals, covers up, falsifies, or makes a false entry in any record, document, or tangible object with the intent to impede, obstruct, or influence the investigation or proper administration of any matter within the jurisdiction of any department or agency of the United States" could face a prison term of up to 20 years.

No, the jails are not filled with people convicted of withholding information from Congress. But some government officials have been prosecuted for it over the years.

None of that is to say Clinton should be charged with any crime. But it does show that the law, and the people who make the law, take concealing information from Congress seriously. It doesn't matter if the material was under subpoena from Congress or whether it was under some other sort of request or demand from lawmakers. As the law sees it, concealing information is not acceptable.

And yet that is what Clinton did. She created and operated the server. She had access to her own communications. She received the September 20, 2012 letter from the committee, addressed to her, requesting "all information" on Benghazi. By her own account, she had 850 pages of emails that fit that description. And she did not turn them over.

2012 passed, and Clinton did not turn over the 850 pages. 2013 passed, and she did not turn them over. 2014 passed, and she did not turn them over. Only in 2015, after Congress learned what was going on, did the House receive the information.

Clinton and Congress are still arguing over whether she has now turned over everything that would be relevant to the Benghazi probe. But we already know she withheld information.