True, here the fMRI is being used by the defense as a means to elude the death penalty, and only in the sentencing portion of the trial—not as a tool of conviction, as a dubious EEG scan was used to convict a woman of murder in India last year. Specifically, the fMRI scan is being submitted as evidence that the defendant Brian Dugan's brain is abnormal—psychopathic—and so he shouldn't be subject to the death penalty. The jury disagreed, but took 10 hours to reach the decision that the state should kill Dugan for his crime. Without the scan, Dugan's defense attorney says it would've take them an hour.

It's kind of hard to grasp, conceptually, looking inside somebody's brain, literally peering into their mind. It's something from fiction, something paranormal—mind readers and psychics—as a means of detection, a means of determining right and wrong, truth and lies. Brain scans to determine how much punishment your crime merits logically leads into brain scans that figure out whether or not you committed the crime, into scans that reveal every crime you have committed, a persistent and inescapable confessional. What secrets would your brain spill? [Science Mag via Wired]