Much effort has been put into making sense of Adam Lanza -- the painfully shy 20-year-old with severe learning difficulties who gunned down 20 young children with a semi-automatic weapon. According to the Stamford Advocate, citing a source in the investigation, investigators have only recently discovered that Lanza kept "reams of documents related to 'virtually every mass murder' in the United States and abroad, the source said."
Lanza exhibited particular interest in the October 2006 shooting at a one-room Amish schoolhouse in Lancaster County, Pa., in which gunman Charles Carl Robert IV took hostages and shot 10 school girls, five of them fatally, before killing himself.
"There was a lot of material on the Amish case," the source said.
... Investigators had been handicapped in determining a possible motive for Lanza's rampage because he destroyed the hard drives of the two computers he used before driving to the school.