Judith Miller (born January 2, 1948) is an American journalist and commentator. She worked in The New York Times' Washington bureau before joining Fox News. Accused by, among others, Edward Said, for a purported anti-Islamic bias in her writing, Miller became embroiled in controversy after her coverage of Iraq's Weapons of Mass Destruction (WMD) program both before and after the 2003 invasion was discovered to have been based on the inaccurate information in the intelligence investigations, particularly those stories that were based on sourcing from the now-disgraced Ahmed Chalabi. The New York Times later determined that a number of stories she had written for the paper were inaccurate.

On October 12, 2001, Miller opened an anthrax hoax letter mailed to her New York Times office. The 2001 anthrax attacks had begun occurring in the wake of the September 11 attacks in 2001, with anthrax-laced letters sent to ABC News, CBS News, NBC News, and the New York Post, all in New York City, as well as the National Enquirer in Boca Raton, Florida. Two additional letters (with a higher grade of anthrax) were sent on October 9, 2001, to Senators Tom Daschle and Patrick Leahy in Washington. Twenty-two people were infected; five died. In 2008, the government's investigation of these mailings focused on Bruce Ivins, who later committed suicide, with the investigation determining that Ivins acted alone.  Miller was the only major U.S. media reporter, and The New York Times the only major U.S. media organization, to be victimized by a fake anthrax letter in the fall of 2001. Miller had reported extensively on the subject of biological threats and had co-authored, with Stephen Engelberg and William Broad, a book on bio-terrorism, Germs: Biological Weapons and America's Secret War which was published on October 2, 2001. Miller co-authored an article on Pentagon plans to develop a more potent version of weaponized anthrax, "U.S. Germ Warfare Research Pushes Treaty Limits", published in The New York Times on September 4, 2001, weeks before the first anthrax mailings.  Miller also participated in a senior-level bio-terror attack simulation on Oklahoma City conducted on June 22 and June 23, 2001, called "Operation Dark Winter"; her role was media reporter/observer.

Using a quote from the above article, answer the following question: What was the content of those letters?
additional letters (with a higher grade of anthrax)