Oh, boy. Now I have to go find the federal statute and cite it for you. What you have posted are the congressional rules for finding a witness in contempt, which as I said is different from the federal statute (that's a law, bigeasy) that makes it a felony to interfere.
Give me minute or two.
Those aren't the House Rules. It is a paper that outlines Congress' authority with respect to investigative powers. Look at 2 USC 192 and 194.
You need to recognize that the law surrounding legislative is fairly unclear especially with respect to third parties who tamper with evidence and witnesses. I cannot think of situation similar to this one.