His wife, Sonya Kukalis, said: "It should be an eye-opener for everybody. Everyone always thinks it's the other neighborhood, the other town. We need to be kinder and show compassion to more people. Something must have been going on for him to do this."
While several bloody stabbing rampages at schools in China have made headlines in the past few years, schools in the U.S. have concentrated their emergency preparations on mass shootings.
Nevertheless, there have been at least two major stabbing attacks at U.S. schools over the past year, one at a community college in Texas last April that wounded at least 14 people, and another, also in Texas, that killed a 17-year-old student and injured three others at a high school in September.
On Wednesday, Mia Meixner, 16, said the rampage touched off a "stampede of kids" yelling, "Run! Get out of here! Someone has a knife!"
The boy had a "blank look," she said. "He was just kind of looking like he always does, not smiling, not scowling or frowning."
Meixner and Moore called the attacker a shy boy who largely kept to himself, but they said he was not an outcast and they had no reason to think he might be violent.
"He was never mean to anyone, and I never saw people be mean to him," Meixner said. "I never saw him with a particular group of friends."
Michael Float, 18, said he had just gotten to school when he saw "blood all over the floor" and smeared on the wall near the main entrance. Then he saw a wounded student.
"He had his shirt pulled up and he was screaming, 'Help! Help!'" Float said. "He had a stab wound right at the top right of his stomach, blood pouring down."
Float said he saw a teacher applying pressure to another student's wound.
About five minutes elapsed between the time the campus police officer summoned help over the radio at 7:13 a.m. and the boy was disarmed, the police chief said.
Someone, possibly a student, pulled a fire alarm during the attack, Seefeld said. Although that created chaos, the police chief said, it emptied out the school more quickly, and "that was a good thing that that was done."
Also, a girl with "an amazing amount of composure" applied pressure to a schoolmate's wounds and probably kept the victim from bleeding to death, said Dr. Mark Rubino at Forbes Regional Medical Center.
Public safety and school officials said an emergency plan worked as well as could be expected. The district conducted an emergency exercise three months ago and a full-scale drill about a year ago.
"We haven't lost a life, and I think that's what we have to keep in mind," said county public safety spokesman Dan Stevens.
Associated Press writers Mike Rubinkam in Allentown and Jesse Washington in Murrysville, Pa., and AP news researchers Judith Ausuebel and Barbara Sambriski contributed to this report.
- Rubber chickens, afros and clowns: A look at...
- Why Utahns are some of the biggest spenders,...
- Immigration reform will boost the economy,...
- As Ferguson verdict is read, protesters in...
- Ferguson businesses torched in overnight...
- Ferguson protesters across US peaceful,...
- Steven Powell ordered to serve more jail time...
- Review: 4 shopping apps that will save you money
- As Ferguson verdict is read, protesters... 68
- Grand jury won't indict Ferguson cop in... 30
- Obama: Americans want 'new car smell'... 29
- Winners and losers under Obama's... 18
- Ferguson businesses torched in... 17
- Under pressure, Hagel steps down as... 15
- Obama immigration plan good, not great... 13
- Obama heads to Chicago to pitch... 13