The FBI is questioning a person of interest who may be involved in sending letters laced with the poison ricin to NewYork Mayor Michael Bloomberg and President Obama. ABC News: The agents are questioning a man from New Boston, Texas, whose wife called authorities after she noticed strange material in her refrigerator, and noticed computer searches for ricin, the source said. The source called the development a promising lead in the case. Images obtained exclusively by ABC News of one of the threatening letters sent to New York Mayor Michael Bloomberg show the substance authorities suspect is ricin. The images show globs of a pinkish, tan substance splattered on a typed letter bearing an anti-gun control message. A similar letter was sent to President Obama at the White House and a Bloomberg-connected office in Washington D.C., police said. "You will have to kill me and my family before you get my guns," the letter reads. "Anyone wants to come to my house will be shot in...(Read Full Post)