A day after a Murrysville, Pennsylvania, teen allegedly rampaged through his high school's hallways, stabbing wildly with two kitchen knives, the first hints of a possible motive began to emerge.
The attorney for 16-year-old Alex Hribal raised the specter that his client may have been bullied, telling CNN affiliate WTAE in Pittsburgh on Thursday that it looks like some kind of "bullying event" may have played a role.
"I think a lot of things have happened. I don't want to comment specifically, but I think there are some things that occurred that led to where we are today," Patrick Thomassey said.
But an FBI official, familiar with the investigation, discounted bullying as a motive.
"He was disaffected but not bullied," the official said on condition of anonymity.
Hribal, a sophomore, was charged as an adult and faces four counts of attempted homicide and 21 counts of aggravated assault in connection with Wednesday's attack at Franklin Regional Senior High School that left 20 teens and one adult wounded.
Some classmates at the school describe Hribal as having few friends and being quiet but also as a "really nice kid," a description that contradicts the image of a knife-wielding teen offered by authorities.
Murrysville Police Chief Tom Seefeld said investigators haven't yet made sense of the mass stabbing.
"We believe, through the investigation, that this was random," he told CNN's "New Day." "We don't have anybody that was targeted, as far as we know at this point."
Still, there were more questions than answers about what led the teen to allegedly attack his classmates with two steak knives believed to have been taken from his family's home.
"We're going to try to figure out what happened here. Obviously, there's a problem. You just don't leave and go to school, and do what he did yesterday," Thomassey told CNN earlier in the day.
There is "some deep-rooted problem somewhere that caused him to do this."
One thread that police are looking into is the possibility that there was a phone threat the night before, Seefeld said.
But no immediate evidence has been found to confirm such a call, and Thomassey discounted the allegation.
"He was home all night the night before this occurred, with his parents," he told WTAE. "They did not see him on the phone arguing with anybody."
The FBI has seized electronics belonging to Hribal, including a computer and cell phone, and will analyze them for any clues, the police chief said.
In a telephone call Thursday, President Barack Obama assured Franklin Principal Ron Suvak that the FBI will continue to assist in the investigation, the White House said.
See more on this story at CNN.com.
A group of low-income and first-generation prospective college students were the victims of a fiery freeway crash that killed 10, including five youths.
It was a trip to open doors and possibilities for the students, but it was cut short by a horrific crash.
Three buses - two from the Los Angeles area and one from the Fresno area - were en route Thursday evening to Humboldt State University in Arcata when a FedEx truck crossed a median and slammed head-on into one of the buses.
The collision killed both drivers, five students and three chaperones, said Lt. Bruce Carpenter with the California Highway Patrol.
The crash resulted in a fire that engulfed the truck and bus, spewing black smoke.
"I went outside, and everything was in flames already," a local resident, Luis Lopez, told CNN affiliate KXTV. "There were a couple of explosions after that."
The reason the FedEx truck crossed the median remains under investigation, the Highway Patrol said. The investigation could take months.
At least 34 people were taken to local hospitals, authorities said.
The collision occurred in Orland, about 100 miles north of Sacramento.
One of the survivors chronicled his experience through Twitter.
"i was asleep and next thing you know i was jumping out for my life," Jonathan Gutierrez wrote, saying he couldn't believe what just happened.
He wrote that he suffered a bruised leg, cut eyebrow and scratches. Later, he said his left leg was injured to the point that he couldn't walk.
"All my stuff that I packed is burned. I'm beyond thankful that I'm still here," Gutierrez tweeted.
He called the experience traumatizing.
"Seeing everyone hurt was not how (I) expected my day to go," he said.
The other two buses made it to the university, and those students were placed in dorms, Humboldt officials said.
The university is offering counseling to those students.
An annual university program brings low-income and first-generation college prospects to campus each year for a two-day visit.
The students stay in residence halls, attend events and visit with staff and students from a program that helps historically underrepresented students, the university said.
The Los Angeles Unified School District confirmed that there were 19 students from the district on the trip but that many other districts had students on board as well. District officials could not confirm whether any LAUSD students were among those killed or the conditions of their students.
"Our thoughts and prayers are with everyone involved in the tragic accident on I-5 in California. We are cooperating fully with authorities as they investigate," FedEx spokeswoman Bonnie Kourvelas said.
The truck sideswiped another car before crashing into the bus. The two occupants of that vehicle were not seriously injured but were sent to a hospital for treatment.
The National Transportation Safety Board announced Friday that it is sending a team to California to investigate as well.
"One, we're going to be investigating the human, the machine and the environment, and what's critical for us especially in highway accidents if for us to collect perishable information, the kind of information that goes away very quickly," NTSB Member Mark Rosekind said.
The NTSB's role will be to determine whether anything from the accident could have a national impact.
The agency seeks to determine not just what happened but why it happened, Rosekind said.
"And then the most important thing we can do is issue recommendations so that these kinds of accidents don't happen again," he said.
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CNN’s popular original series "Morgan Spurlock Inside Man," produced and hosted by documentary filmmaker Morgan Spurlock, will return on Sunday, April 13, 2014 at 10pm ET/PT.
His talked about his first subject, celebrity – and the job of satisfying the public's constant appetite for the famous, on "New Day" Friday.
Watch the clip above to see Spurlock share his experience trying to snap a picture of basketball star Lamar Odom .