In the U.S., violence directed toward abortion providers has killed at least nine people, including five doctors, two clinic employees, a security guard, and a clinic escort. According to statistics gathered by the National Abortion Federation (NAF), an organization of abortion providers, since 1977 in the United States and Canada, there have been 17 attempted murders, 383 death threats, 153 incidents of assault or battery, and 3 kidnappings committed against abortion providers.[10] The attempted murders were:[5][11][12] The first letters claiming to contain anthrax were mailed to U.S. clinics in October 1998, a few days after the Slepian shooting, and since then, there have been a total of 655 such bioterror threats made against abortion providers. None of the "anthrax" in these cases was real.[11][14] According to NAF, since 1977 in the United States and Canada, property crimes committed against abortion providers have included 41 bombings, 173 arsons, 91 attempted bombings or arsons, 619 bomb threats, 1630 incidents of trespassing, 1264 incidents of vandalism, and 100 attacks with butyric acid ("stink bombs").[10] The first clinic arson occurred in Oregon in March 1976 and the first bombing occurred in February 1978 in Ohio.[15] More recent incidents have included:[5]