Can Screening Predict Murder?

In the early morning hours of Oct. 7, following a confrontation with his on-again, off-again girlfriend, a 20-year-old off-duty deputy sheriff and part-time police officer grabbed his police-style AR-15 assault rifle and fired off 30 shots, killing her, five of her friends, and critically wounding another in her home, where they had gathered to eat pizza and watch movies during the high school's homecoming weekend. Several hours later, the shooter, Tyler Peterson, was dead, also of gunshot wounds. That morning, the town of Crandon, Wisconsin, population 2,000, changed forever.

Since then, much has been made of the fact that such a young person held a law-enforcement position, and that, on top of that, he had undergone no psychological testing before his first day on the job. Compared to many other communities, his age was not remarkable; the minimum age is quite often 18 or 19. While it is true that most states do require psychological testing before law-enforcement officers hit the streets, and that Wisconsin does not, there is no guarantee that such screening could have prevented Peterson's hiring. And definitely no guarantee--- or even reasonable degree of probability--- that testing would have, in turn, prevented his vicious attack.

If they know, investigators have not revealed if Peterson's weapon was issued by the sheriff's department or was Peterson's own rifle. Contrary to earlier reports that he had been felled by a police bullet, an update by the state's attorney general claims that Peterson's death was caused by self-inflicted gun shots from his own Glock pistol. Many of Crandon's grieving residents, the stunned family and friends of the victims and of the shooter, and the state's news reporters seem to have concluded that had Peterson undergone psychological testing, this would not have happened. While it may be safe to maintain that a normal person could not have done such a thing, whether the murders could have been prevented is not as clear.