Way easier than you think... just look in the phone book under women´s services. Look up the address of the clinic. Go to that clinic and wait until the guy in the exotic sports car rolls in and takes his reserved spot. That will be your local mass murderer.

Not just "no easy task", but rather an "impossible" task. Consider meteorology. It is a scientific discipline considering a handful of simple and easily-measurable phenomena: relative humidity, wind direction and speed, atmospheric pressure, and the like. Read Edward Lorenz and others from the 1960s onward. Then consider how it becomes more iffy to "predict" next week´s weather, or freak storms. Can the people trying to "predict" human behavior even specify (and importantly: "measure and quantify") the variables, as a meteorologist can?

Most likely, people around these mass killers had noticed increasingly alarming signs.

But you can´t go to the police and say you "think" something is going to happen, unless you know there´s a specific threat.

So people are left to try to access mental health services. Then again, you can´t force people to take their meds, for example. There was a case on Cape Cod where a kid had threatened his mother. He was to get his meds at a local hospital every day. He failed to show up one day. They called the mother ---too late. She was found, her son had killed and decapitated her.

This is a difficult and probably intractable problem... because we do not live in a utopia. Life is full of troubles, suffering, the unplanned horrors... along with what is good, and true and lovely.

So, no matter how hard totalitarians try, hazards can´t be eliminated from life. Rational people will try to do what is rational and not act in haste.

The first "remedy" totatalitarians apply is new and increasingly pervasive restrictions on liberty. (Think about the obamacare bill, for example.)

#3, you are spot on. The problem with these ´studies´ is that they start with an assessment by a stranger. Start by listening to the family and friends. They know when a person is becoming more and more unstable. But current laws forbid the mental health professionals to even speak with family and friends without the express permission of the patient! How stupid...imagine a fireman needing express permission from the property owner before starting to put out a fire. Or needing express permission from the parent of a drowning child before attempting a rescue. When a person with serious mental illness is destabilizing, he/she isn´t always capable of giving permission. Let the medical pros get pertinent info from whatever sources are available...and save lives.

obama and eric holder. Sellers of assault rifles to Mexican drug cartels. Over 300 men, women, children murdered. Just look obama and holders at their arrogant faces.

Let the ACLU create a test to identify mass killers and then we put them to death. Problem solved.