Thorough piece by N.R. Kleinfield in Sunday's Times on the upbringing of Seung-Hui Cho. This was one of the crazier points:

His junior-year roommates mostly ignored him because he was so withdrawn. If he said something, it was weird. During Thanksgiving break, Mr. Koch recalled, Mr. Cho called him to report that he was vacationing in North Carolina with Vladimir Putin, the Russian president; Mr. Cho said he had grown up with him in Moscow.