Quote from tonights show according to this article i just read :

"All along it was YOU," Hank seethes in the opener. "I will put you under the jail!"

"In six months you won't have someone to prosecute," taunts Walt, who, after all, is dying from terminal cancer. Then he adds as a barely veiled threat: "Maybe your best course would be to tread lightly."

http://www.silive.com/entertainment/tvfilm/index.ssf/2013/08/breaking_bad_star_dean_norris.html

Good article, check it out.