SANTA MONICA, California (CNN) -- What would compel a man to take his father's and his brother's lives, and then go on a shooting spree at his former college, killing three other people in the next 13 minutes?
The Friday afternoon rampage in Santa Monica, California, ended only when police shot dead the suspect, John Zawahri.
Over the weekend, bits and pieces about the 23-year-old emerged.
But with his death, a day shy of his 24th birthday, the central question may remain unanswered.
He had suffered mental health issues and was hospitalized a few years ago after allegedly talking about harming someone, a law enforcement source said.
Police had contact with him in 2006 -- but because he was a high schooler, and therefore a juvenile at the time, police couldn't disclose more.
And as recently as 2010, he attended Santa Monica College -- where he met his chaotic end in the school library.
'I'll never forget his eyes'
Police say the spate of violence that left this beachfront city reeling on Friday involved as many as six incidents over 13 minutes.
It started at Zawahri's house on Yorkshire Avenue shortly before noon, and ended a mile away in the college library where students were studying for finals.
Officers were dispatched to the house to respond to reports of shots fired. There, they found the 1,000-square-foot home in flames.
Inside, firefighters would later find two bodies in a back room -- that of Zawahri's father, Samir, and his brother, Chris.
Both had been shot dead.
Outside the house, police came across an injured woman who too had been shot: Deborah Fine.
Fine told CNN she was driving when she saw the gunman pull over another woman and hold a rifle to her head.
"I thought to myself, 'What are you doing? Why are you pointing this gun at her?' And so I put on my accelerator, I hit the gas, and I got in between the two of them," Fine said.
The bold move quickly turned the gunman's attention to Fine.
"I'll never forget his eyes. They were just so intense and so cold," Fine said. "That's when he raised his rifle."
The bullets struck Fine three to four times across her body.
With blood pooling around her body, she slumped over and played dead in hopes that the gunman would stop.
When neighbors rushed to the scene, Fine had one plea:
"Please, I don't want to die. I have twins. Just please open my car door," she said.
Fine still has pieces of shrapnel inside her body.
The next two victims
Fine had interrupted his carjacking. But with her wounded, the gunman's rampage was just beginning.
He got into the carjacked vehicle and forced his victim to drive the short distance to Santa Monica College.
During their ride, 911 calls poured in, keeping police on the gunman's path.
As the car headed toward the campus of the community college, where 30,000 students are registered, he opened fire on a passing bus, slightly wounding three people.
Then, he got out and shot into a red Ford Explorer, carrying 26-year-old Marcela Franco and her father, 68-year-old Carlos Navarro Franco. The pair was on campus to get textbooks for Marcela.
Carlos Franco was a groundskeeper at the college. He died shortly after the shooting.
Marcela Franco wanted to be a clinical psychologist. She was taken off life support Sunday.
"We spent last 48 hours like (in) a cocoon. Nobody else in there. Just us," said family member Margret Quinonez Perez. "We were loving her, telling her how much we loved her. We're going to miss her."
"'Broken' is not a strong enough word to describe us," she added.
'He executed her'
After shooting into the SUV, the gunman abandoned his hijacked vehicle -- leaving the driver unhurt.
Dressed in black and wearing a ballistic vest, he then walked the campus, "shooting as he went along," said Santa Monica Police Chief Jacqueline Seabrooks.
Outside the school library, he came saw a woman and "he executed her," Seabrooks said.
Her death was the fifth of the rampage. Her name was not released.
Gunfight in the library
By all accounts, the gunman was ready to inflict maximum harm. He had about 1,300 rounds of ammunition and multiple firearms.
He went into the school library and fired several times at terrified patrons who were hiding in a safe room.
Police called it "miraculous" that they were not wounded.
Jasmine Franco was in a classroom next to the library -- waiting for her English class to start.
"You could hear rumbling, a lot of rumbling, it sounded like an earthquake or something," she said, referring to the sounds of gunfire mixed with the footfalls of people running.
Inside the library, Priscilla Morales and her friends hid.
"I was so scared and thought literally I was going to die," she said.
By then, the gunman had returned to the main area of the library, he was met with three police officers.
"Drop it!" Morales said she heard police say.
Then she heard gunshots and a man's screams.
Officers had shot and killed Zawahri.