I didn't even realize that they had caught the guy. The slashings are such a violation not only because they are the cute animals that our kids love to see but because the park is so open. You are allowed to wander and look at animals, including going inside the horse area which is somewhat removed and kind of a special place.
Apparently the crud used a machete that he carried around with him.
Conviction
http://www.washingtonpost.com/blogs/crime-scene/post/herndon-teen-convicted-in-horse-slashings/2012/08/16/5de094d0-e7e1-11e1-8487-64e4b2a79ba8_blog.html
Background
http://www.washingtonpost.com/local/crime/teen-arrested-in-fairfax-animal-slashings/2012/06/25/gJQAemZl2V_story.html