dr. jeffrey liebermann, a psychiatrist at columbia university. >> usually when one of these situations happens, the... you'll hear in the media that this was a nice quiet boy that never created any problem but then after a few days go by we begin to see that there were a number of these indicators, warning signs. cho or harris and klebold, of course, had a web side where... it was just filled with angry denunciations of classmates and people in general and how they would like to kill people. so some of the things that we would look for and what we would see and hear, if there are 25 indicators, general indicators, this shooter had about 10 or 12 of the 25. >> there's i think sufficient information that's available by virtue of people who knew him, students that were classmates with him, teachers that has been... what his parents reported. his postings on the internet, his youtube to say that a high probability or almost a certainty that he suffered from a severe mental disorder almost certainly psychotic disorder and of the psychotic disorders, the most likely candidate given his age and his m