Reconstructing Adam Lanza's hard drive

Adam Lanza's hard drive is destroyed. Mr. Lanza, the 20-year-old who killed 27 people and himself in Newtown, Conn., last week, smashed his computer the morning of the attacks. Investigators are trying to put Adam Lanza's hard drive back together -- but even if they fail, there might be other ways to see what Lanza was doing before the shootings.

As children return to school in Newtown, Conn., police are beginning to sift through available forensic evidence in hopes of determining why gunman Adam Lanza killed his mother, 26 students and staff at Sandy Hook Elementary School, and himself. It's a process complicated, though, by the fact that Mr. Lanza didn't leave much of a technological trail for investigators to follow.

First, there's Lanza's own computer, which might have held clues about who he communicated with or what he was doing leading up to the attack.

On the morning of the attack, Lanza apparently removed the hard drive from his computer and destroyed it with a hammer or screwdriver, doing such a thorough job that the Connecticut State Police, assisted by the FBI, haven't been able to recover any information from it yet. A source told The Daily Beast that the FBI's computer analysis team is trying to put the pieces of the hard drive back together, but hasn't had any success yet in recovering Lanza's e-mails or the websites he visited.

That's not to say that that information is gone forever, though. If investigators can't coax any information from the mangled hard drive, they might be able to find out about Lanza's online activities from other sources.

Many e-mail providers, such as Yahoo and Google, store data on their servers for a period of time, meaning that police might be able to subpoena Lanza's provider for access to whatever data they have. Google also stores information about users' searches and other online activity indefinitely, although it anonymizes IP addresses after 9 months, making it impossible to tell what a given user was doing online prior to that time.

Google says it tries to strike a balance between respecting users' online privacy and complying with government requests for information, and this might be a case where the company deems it important to cooperate with law enforcement.

In terms of overall online activity, though, Lanza kept a pretty low profile. In contrast to many people his age, the 20-year-old didn't have a Facebook or Twitter account.

Early reports of the shooting named Lanza's older brother Ryan as a possible suspect, and several news outlets mistakenly published pictures of Ryan taken from his Facebook account.

In the absence of the kind of public journaling often seen on social media sites, law enforcement will have to rely more heavily on interviews and other sources to determine a possible motive for the shooting.

Lanza seems to have guarded his digital privacy pretty closely -- but as we've seen in previous cases involving computer privacy, it's awfully difficult not to leave behind some kind of trail of e-mails and online behavior. Even if Lanza's hard drive yields no clues, investigators could still find a way to reconstruct some of his activity in the days and months leading up to the shooting.