AURORA, Colo. - On the morning of the latest mass shooting, in a place that has become synonymous with tragedy, Tom Mauser's phone started ringing at 5 a.m. When he turned on the news his first thought was "Oh God," followed by an immediate: "Not again."
He's seen this too often since that April morning in 1999, when his own son Daniel was slain along with 12 others at Columbine High School. In the years that have followed, every time the unthinkable happens yet again - at a Virginia college, a Texas military base, an Arizona strip mall, a Colorado movie theater - Mauser mourns anew.
But he also feels something else, the frustration we all feel when we see the same images we've seen before: Hysterical victims fleeing in terror. Anguished mourners crying out for lost loved ones. Stunned citizens praying together at candlelight vigils.
"There was a time when I felt a certain guilt," said Mauser, a state transportation program manager who became an outspoken activist against such violence after his 15-year-old son was killed. "I'd ask, 'Why can't I do more about this? Why haven't I dedicated myself more to it?' But I'll be damned if I'm going to put it all on my shoulders.
"This," he said, "is all of our problem."
But where to begin solving it? In a nation that likes its quick-fixes and finger-pointing, do we blame the mental health industry, poor parenting, a 24-7 news cycle that brings instant "fame" to mass murderers and sometimes spawns copycats, a culture that glamorizes - and has become desensitized to - violence in its many myriad forms? (Consider the nonstop Internet "zombie" chatter after a Florida man this year had his face nearly chewed off in a bizarre attack.)
And placing blame aside, are there steps we can take to prevent yet another rampage?
Mauser's primary focus has been to advocate for more gun control. The year after Columbine, he helped lead an initiative approved by Colorado voters to require background checks for all firearms buyers at state gun shows.
Still, that didn't prevent accused Aurora shooter James Holmes from acquiring two pistols, a shotgun, an AR-15 rifle and thousands of bullets. Someone intent on killing will find a means. And so Mauser and those who have spent years studying mass murder know that any so-called solutions must go far beyond gun control.
Generally, they say the solution may have less to do with government intervention than individual action. People need to be more aware of troubled individuals who may act violently; they should talk with them, and if they remain alarmed they must reach out for help. And when they do, there must be someone to listen and act effectively.
"The question we have to ask constantly is: What more can we be doing? We may not be able to stop all of them, but I think we could stop more than we do," said Peter Langman, a psychologist who has spent years studying the Columbine massacre and similar incidents at other schools and universities.
In many cases, Langman and others have found, the murderers either left clues as to what might be coming or behaved in a manner that left those around them feeling uneasy but, perhaps, unsure of what to do.
Langman points out that not long before Dylan Klebold and Eric Harris opened fire at Columbine, Klebold's school compositions - including descriptions of a killing - so disturbed a teacher that they were brought to the attention of his parents. But Klebold explained them away as mere fiction, and the shootings happened a short time later.
"Many school shooters have told people exactly what they were going to do, but nobody believed them," said Langman. "Nobody took them seriously."
Jared Loughner, accused in the January 2011 shooting in Tucson, Ariz., that killed six people and wounded former U.S. Rep. Gabrielle Giffords and 12 others, had several run-ins with police while studying at Pima Community College in Tucson.
Some 51 pages of campus police reports described a series of classroom outbursts and confrontations that prompted worried instructors to summon campus officers. He was suspended and later withdrew from school. But even now some still ask whether the college could or should have done more by taking any concerns elsewhere - to mental health professionals, perhaps.
Similar questions have been raised in the case of Holmes, who had recently withdrawn from a competitive graduate program in neuroscience at the University of Colorado Anschutz Medical Campus. Officials there are looking into whether Holmes used his position in the program to collect hazardous materials, but it remained unclear whether Holmes' professors and others in his 35-student Ph.D. program noticed anything unusual about his behavior.
Langman understands the hesitation private citizens and institutions may have about acting on instincts. We're not psychiatrists, after all. What if the person in question has broken no laws? Who am I to say something?
His response: "You can alert people. You can try talking to the person if it's someone you know. Engage them in conversation. See if they're in a state of crisis."
In a post-Sept. 11 world, if we see someone on a subway or an airplane doing something suspicious, we don't hesitate to report it. Why would we waver in these situations?
Perhaps the threat seems less immediate. Perhaps the difference is in reporting the suspicious activity of a stranger rather than someone we know and, possibly, love.
Terry Garahan, who spent years training law officers in Ithaca, N.Y., to better cope with emotionally disturbed suspects, has another take.
"Institutionally, we have become like the people who saw Kitty Genovese stabbed to death," said Garahan, recalling the 1964 stabbing of a woman in New York witnessed by some 38 people who never alerted authorities. "We assume that someone else is going to take care of it, someone else is going to make the call. What we can do is to take a risk."
In the late 1990s, after a patient at a mental health clinic Garahan supervised killed a police officer and was then herself killed on scene, Garahan and Ithaca police teamed up to respond to calls from parents, co-workers, strangers or neighbors about individuals who might do harm to themselves or others.
"At times, they slammed the door in my face. At other times I was threatened. At times they pointed guns at us. But there has to be somebody who is willing to do this, and law enforcement is only equipped to do part of it," he said.
The program continues today. And, certainly, there are numerous other examples of preventative measures that have been put into place in the wake of mass killings.
At the University of Virginia, forensic clinical psychologist Dewey Cornell leads a project that has developed assessment guidelines to help identify threatening individuals that are now used in most public schools in Virginia as well as other communities across the nation, in Canada and in Europe. In the wake of the 2007 rampage at Virginia Tech that left 33 people dead, including the shooter, many colleges and universities established assessment teams. Cornell serves on his at UVA.
In an e-mail, he said: "There is a widespread misperception that rampage shootings cannot be prevented because they seem so random and unpredictable. However, it is possible to prevent outcomes that are hard to predict."
But how do you cover all your bases? After all, these rampages have happened at fast-food restaurants, rural cafeterias, offices, a health club, a nursing home, an Amish school.
"We're not going to turn our country into one big fortress," said James Alan Fox, a professor of criminology at Northeastern University and one of the nation's foremost experts on mass murder. "People hate when I say this but it's true: This kind of tragedy is one of the unfortunate prices we pay for our freedoms."
If there is one saving grace it is to be found in statistics. Fox has collected data on every mass murder in the United States going back to the mid-1970s and, though we certainly see and hear about these incidents more quickly today, the numbers of such incidents have not increased over time. He counted 19 in 1976 and 18 in 2010, with the range going from a low of seven in 1985 to a high of 30 in 2003. The FBI defines a mass murder as one in which four or more people are killed.
In fact, he and others noted, overall homicide rates in the United States have fallen to their lowest levels in decades. And while America still suffers from more violent crimes and murders than most other westernized countries, mass killings occur elsewhere, as well.
Norway just marked the somber one-year anniversary of the twin attacks in downtown Oslo and at a youth camp outside the capital that killed 77. Finland saw two back-to-back mass shootings at schools in 2007 and 2008. Germany, too, has experienced several homicidal attacks at schools, prompting officials there to contact Cornell about his threat assessment techniques.
Fox has studied these killings too much to think there are any hard and fast solutions. Beyond gun control, most Americans will look to the mental health industry for accountability. (In the Aurora shootings, no evidence has surfaced to date to determine if Holmes may have suffered from mental illness.) If better mental health treatment is one result of this latest tragedy, said Fox, "lots of Americans will be better off, but the few at the extreme who commit this kind of crime will not avail themselves of that.
"When people say there were warning signs, they're yellow flags," he added. "Those yellow flags only turn red once the blood has spilled."
In Aurora, as residents gathered Sunday night for a prayer vigil to remember the victims of Friday's shootings, Coloradans were grappling with these very questions, and the knowledge that there may be no real answers.
"You can always come up with ideas, but people who are bound and determined are going to find a way around your ideas. So it's almost a lost cause at some point," said 28-year-old Debra Wahl, who stood gripping a state flag next to her 19-year-old cousin, Leeza Pearson.
"You've just got to hope nothing happens," said Pearson, the soaring neon sign of the movie theater hovering in the horizon beyond her gaze.