If you are into homeland security oriented data mining, this post is for you.
The University of Maryland has a Global Terrorism Database (GTD; http://www.start.umd.edu/gtd/) with information on over 80,000 terrorist attacks that intelligence researchers can tap into.
GTD is an open-source database including information on terrorist events around the world from 1970 through 2007 (with annual updates planned for the future). Unlike many other event databases, the GTD includes systematic data on domestic as well as international terrorist incidents that have occurred during this time period and now includes more than 80,000 cases.
You can search by keywords or browse by region, country, perpetraror, weapon, attack, or target.
It also has advanced search capabilites. To perform an advanced search you need to select all categories you wish to search. If you do not check any options then your search will include all content from that category, for example, selecting Algeria from the “Country” list will restrict your search to incidents in Algeria, while leaving it blank searches all countries.
Incident searches can be restricted to specific years using several pull-down menus.
I tested by querying [puerto rico] and indeed was able to obtain incident records related with Los Macheteros. The answer set, however, included results not relevant to the Island of Puerto Rico.
The database is pretty small, but can come handy at times. Definitively, I will use it for one of my next graduate courses on search engine architectures.