The crime rate in Seattle has been volatile since about 2005. There are several factors behind the crime trends including changing demographics, police staffing, and the city's growing pains. Most of the crime data you'll find online is weeks or even months out of date. For the most up-to-date information on crime in Seattle, go to the Seattle Police Department crime mapping website: http://www.seattle.gov/police/crime/onlinecrimemaps.htm
The website is interactive and you can use the search functions to narrow your search to specific neighborhoods and specific types of crime. Another website I use is SpotCrime.com. On SpotCrime, you can sign up for email notification of crime events in a radius around an address that you choose. Good luck!