On Tuesday, she was formally charged with murder with a deadly weapon and with one count of leaving the scene of an accident, also a felony, according to a criminal complaint. She faces a third felony, which is child abuse, neglect or endangerment, in connection with her small child's presence in the car.
More charges are expected as the investigation unfolds, prosecutors said Tuesday.
Just three years ago, Holloway spoke of how her life was taking a turn for the better.
"I was a scared little girl who knew that there was more to life outside of crime, drug addiction, lower income, alcoholism, being undereducated -- all of which I grew up being familiar with."
Thanks to the nonprofit, she went from homelessness to a job with the federal government and "living the grand life."
But now, the 24-year-old faces serious charges after allegedly plowing into dozens of pedestrians with her 3-year-old daughter inside her car.
What would cause a woman who showed so much promise to do something so savage, as police claim?
"She would not explain why she drove onto the sidewalk but remembered a body bouncing off of her windshield, breaking it," authorities said in her arrest report.
Changing her name to Paris Paradise Morton
Clark County District Attorney Steve Wolfson indicated more charges are likely.
"Our hearts go out to the victims and their families," the prosecutor said in a statement. "This is a horrendous and inexcusable act that has needlessly and tragically impacted countless lives. I am confident that, as the investigation unfolds, we will be filing many more charges against Ms. Holloway."
Under a new state law that went into effect October 1, leaving an accident scene where an injury occurred is now punishable by up to 20 years in prison and is non-probational, the prosecutor said.
In October, Holloway legally changed her name to Paris Paradise Morton, according to a court judgment in Oregon. Authorities, however, have continued to identify her by her former name.
Clark County Sheriff Joe Lombardo said it's not clear what may have caused Holloway to "snap."
"We believe that she had some disassociation with the father of her child," the sheriff said,
He said investigators think Holloway had been in Las Vegas for about a week, homeless and living in her car.
But a family representative told CNN that Holloway wasn't homeless, had a job and comes from a loving family. The representative declined to comment on what could have prompted the incident.
The sheriff said police don't know what "caused her to snap and/or whether it was planned previously."
Holloway told authorities that before the crash, she had been trying to rest or sleep in her car with her daughter, but kept getting run off by security at the places wherever she stopped, according to her arrest report.
She wound up on the Strip, "a place she did not want to be," the police statement read. Police said she told them she wasn't under the influence of drugs or alcohol.
Witnesses said Holloway was driving down Las Vegas Boulevard before her car jumped onto the sidewalk and started striking pedestrians.
She allegedly drove the 1996 Oldsmobile sedan with Oregon plates onto the sidewalk at different spots. She careened onto the sidewalk at least three or four times, Las Vegas Metropolitan Police Deputy Chief Brett Zimmerman said.
Holloway then left the scene and drove about a mile before driving onto the property of another hotel and contacting a security officer, asking that officer to call the police because she'd just hit several people, according to the arrest report.
Driver 'just kept mowing people down'
Antonio Nassar said people scrambled to stop the woman as she drove on the sidewalk.
"The car rolled right in front of me. By the time I looked over to the right, all you could see was (her) driving away, and people were bouncing off the front of the car," Nassar told CNN affiliate KLAS
"She rode the sidewalk, she came to a stop at the (Paris Las Vegas Hotel) intersection, people are punching into the window. ... She accelerated again and just kept mowing people down."
Another witness, Sofie Kitteroed, told CNN that bystanders rushed to the scene to help bleeding victims.
The person killed in the crash was identified as 32-year-old Jessica Valenzuela of Buckeye, Arizona.
Holloway's daughter was not injured.
Meanwhile, three victims were in critical condition Tuesday and two others in serious condition at the University Medical Center of Southern Nevada, said spokeswoman Danita Cohen.
Four members and coaches of Oregon's Pacific University wrestling team have been released from the hospital and have returned to Oregon, a school spokesman said Tuesday. They were among those injured in the incident and are expected to make a full recovery, the spokesman said. They were in Las Vegas for a tournament.
Many questions unanswered
Authorities gave conflicting accounts on whether they are investigating the possibility of terrorism in the crash.
The sheriff said investigators will look into Holloway's background.
"We're not 100% ruling out the possibility of terrorism," Lombardo said.
But Zimmerman, the Las Vegas police deputy chief, said investigators have ruled out terrorism.
"This was not an act of terrorism," he said. "We are treating this as an intentional act."
A roller-coaster life
Portland OIC, the nonprofit that honored Holloway with a C.A.R.E. Role Model Award in 2012, expressed shock over her arrest.
"She was such a great kid while she was a part of our program," one of the youth employment staff members said, according to a POIC statement.
In her 2012 video, Holloway said she was homeless in high school and nearly failing all her classes.
But she graduated with a B+ average, went on to college and started working with the U.S. Forest Service.
"Today, I am not the same scared girl I used to be," she said in the video. "I'm a mature young woman who has broken many generational cycle(s) that those before me hadn't."