This answer is a bit complicated to say the least. You ask me “Is the Investigative Committee similar to the FBI in operation and appearance?” The answer is “it could be, but (and this is a big but) you did not specify the “Investigative Committee”, you are referring to.
A LITTLE HISTORY: (1) Investigative Committee in the UK commonly referred to as “General Medical Council, (UK).”
(2) In the USA there are in fact many different kinds of “Investigations and bodies that perform them as follows”. LEGISLATIVE INVESTIGATION, is a formal inquiry, conducted by a legislative body exercising its legislative authority. A legislature has many of the judicial or quasi judicial powers as a court, to support a legislative inquiry, including but not limited to, “subpoena and cross-examine a witness and to hold a witness in contempt.”
(3) The United States Senate also has the power to conduct investigations. The authority of Congress to investigate is an implied constitutional power. One of our founding forefathers, said something like, James Madison anticipated the significance of congressional inquiry in Federalist 51 when he urged: “In framing a government which is to be administered by men over men…you first must first enable the government to control the governed; and in the next place oblige it to control itself.” These type of investigations are different from regular criminal investigations.
As far back as I have researched, Senate Investigations date back to around 1792 when the House passed a resolution to examine the disastrous St. Clair expedition. Congress has conducted many investigations since its inception but these investigations at the very best, “have managed to achieve a level of bipartisanship to maintain credibility in our government.” (Sort of!)
Particularly during the second half of the 20th century, senators and their committee staff have honed their public relations skills to attract press coverage and hold public attention. Historically significant Senate investigations have uncovered wrongdoing, have punished transgressors, and have produced legislation aimed at prohibiting similar abuse in the future. (But in real life you find that our government is infected with a cancer called corruption, most of the later investigations only address new legislation aimed at prohibiting further abuse, but our own government cover-up for the abusers is they are (a) a government entity, or employee. (b) Rich!)
NOW THAT BEING SAID, INVESTIGATIONS & OVERSIGHT; The Constitution says nothing about congressional investigations and oversight, but the authority to conduct investigations is implied since Congress possesses “all legislative powers.” The Supreme Court determined that the framers intended for Congress to seek out information when crafting or reviewing legislation. George Madison of Virginia said at the Federal Convention that Members of Congress “are not only Legislators but they possess inquisitional powers. They must frequently inspect the Conduct of the public offices.”
(4) The FBI conducts mostly criminal investigations against many different threats against the United States, (Terrorism, Corruption, Civil Rights Violations, and others.) Although getting the FBI to legally act against one of their own is not easy, even when one has thousands of pages and voice recordings against them. We have found that FBI agents hide inside their offices instead of answering legal documents/questions!
So yes the investigation can be similar yet they can be very different! FBI can not prosecute anyone “investigate and arrest yes, the State's Attorney, through the Courts will prosecute”. Hope this helps, should you have specific questions please contact me again. (Please do not hold some of the dates addressed here against me if they are a little off, I wrote they off the top of my head!)