Recent mass killings, such as those in Newtown, Connecticut, and Aurora, Colorado, have brought new attention to mass killings in the United States. This article examines 323 mass killings taking place between January 1, 2006, and October 4, 2016, to assess how they are distributed over time. In particular, we find that they appear to be uniformly distributed over time, which suggests that thei...

The U.S. Department of Justice released the first national guide for collecting and preserving eyewitness evidence in October 1999. Scientific psychology played a large role in making a case for these procedural guidelines as well as in setting a scientific foundation for the guidelines, and eyewitness researchers directly participated in writing them. The authors describe how eyewitness resear...

We used data gathered via investigative "RoundUp" software to measure a year of online child pornography (CP) trafficking activity by U.S. computers on the Gnutella peer-to-peer network. The data include millions of observations of Internet Protocol addresses sharing known CP files, identified as such in previous law enforcement investigations. We found that 244,920 U.S. computers shared 120,41...

Because of the way computers operate, every discrete event potentially leaves a digital trace. These digital traces must be retrieved during a digital forensic investigation to prove or refute an alleged crime. Given resource constraints, it is not always feasible (or necessary) for law enforcement to retrieve all the related digital traces and to conduct comprehensive investigations. This pape...

An area presenting new opportunities for both legitimate business, as well as criminal organizations, is Cloud computing. This work gives a strong background in current digital forensic science, as well as a basic understanding of the goal of Law Enforcement when conducting digital forensic investigations. These concepts are then applied to digital forensic investigation of cloud environments i...