Adam Lanza
Ironcially, Jared Lee Loughner, the shooter in the Arizona mass killing, which claimed several lives, was also into the Goth movement. As were the shooters in the Columbine school killings. The music, films, books, imagery and practices associated with Goth is full of darkness and depressed. To an already unstable mind, the mix equals disaster. There's definitely a link there.
Newspapers have also been pointing out, Lanza played many violent video games at home, which have been linked to killings committed by troubled minds. However, it should be noted, many video game users do not kill or injure others.
Adam Lanza
Authorities are searching for motive in the case, but have been unsuccessful in establishing one, as Lanza was a loner, as was his mother and any evidence on his computer has been destroyed, with police stating he smashed the hard drive to pieces.
Hopefully the Lanza family's internet service provider will be able to give them access to his internet history and accounts online, as by law, said information is supposed to be stored for 2-years (and emails deleted from one's inbox, are also supposed to be stored on servers for the 2-year period).