On Tuesday night, George Sodini executed a terrible plan. He opened fire at an aerobics class in Bridgeville, Pennsylvania, and shot 12 women, 3 fatally, before turning the gun on himself. This was not a spontaneous attack: he had mapped out his plan in painstaking detail in notes kept in an online diary. Those notes now provide a stark look at the mind of a killer. Dr. Michael Welner, a forensic psychiatrist and adjunct law professor at Duquesne University in Pittsburgh, who studies killers, joins us with a look at the psychological profile of a mass murderer.

Criminal justice systems in a number of countries are expanding advanced DNA databases to keep track not only of convicted criminals, but also of people only accused of crimes. But Britain announced today that it plans to scale back its national DNA database. This move follows a ruling by the European Court of Human Rights last year criticizing Britain’s practice of keeping on file the DNA anyone who’d been arrested, even if they weren’t charged with a crime. For more we turn to Naomi Grimley, the BBC's political affairs correspondent.