Police have been unable to recover data from gunman Adam Lanza's computer after the 20-year-old deliberately sabotaged the machine's hard drive, investigators have said.
Forensic experts revealed the software had been smashed so extensively that attempts to retrieve potentially crucial evidence such as emails had failed.
A joint effort to piece together the remains of the hard drive, reported to have been damaged with a screwdriver or hammer, was undertaken by Connecticut State police and the FBI.
Authorities had hoped its data would shed some light on Lanza's killing spree. Detectives have so far been unable to provide any definitive link between the young man and the school he attacked.