premise: On August 19, 1999, I received a letter from Dr. Chopra in which he states that, "I mentioned that all these actions were the direct consequence of my testimony, which I was requested (required) to give before the Standing Senate Committee on Agriculture and Forestry for its bovine growth hormone rBST investigations."
hypothesis: Dr. Chopra received a letter on August 19.
reason: Dr. Chopra mailed the letter. He didn't receive it.