TULSA, Okla. >> An Oklahoma woman who drove into a crowd of spectators at Oklahoma State University’s 2015 homecoming parade, killing four people and injuring dozens of others, is set to stand trial.

Adacia Chambers, 26, has pleaded not guilty to four counts of second-degree murder and 42 counts of assault and battery. If convicted of any of the murder charges, she could face up to life in prison. The trial begins Tuesday in Stillwater.

Prosecutors allege that Chambers steered her car around a police barricade and sped up before she plowed into the crowd watching the parade before Oklahoma State’s game against the University of Kansas. Prosecutors say this showed intent.

Chambers’ attorneys say she has a mental illness and was experiencing a psychiatric episode at the time of the crash. Her father said she received psychiatric treatment at an in-patient facility several years ago.

Here’s a look at some key aspects of the case:

BEFORE THE CRASH

Co-workers at the restaurant where Chambers worked said that the morning of the crash, she had difficulty performing tasks that she normally did well. When her manager confronted her, Chambers “became emotionally distressed,” made reference to quitting and ran to her car, a report by the National Transportation Safety Board found. The crash happened about 10 minutes later.

ACCELERATED

Chambers sped up from 54 to 59 mph in the five seconds before she struck a police motorcycle that was blocking the road along the parade route, according to the NTSB report.

VICTIMS

Killed were Nikita Nakal, a 23-year-old MBA student from India at the University of Central Oklahoma in Edmond, a married couple, Bonnie Jean Stone and Marvin Lyle Stone, both 65, and 2-year-old Nash Lucas. Dozens more were injured, many of them children.

AFTER THE CRASH

One of Chambers’ attorneys, Tony Coleman, has said she was experiencing a psychiatric episode when the crash happened and that when he told her about the deaths after the crash, “her face was blank” and that he wasn’t sure if she even realized she was in jail. Chambers’ father, Floyd Chambers, said she received inpatient mental health treatment several years ago. The judge, though, ruled that Chambers was competent to stand trial and refused a defense request to move the trial to another jurisdiction.

THE TRIAL

The trial could last a month, as prosecutors have an extensive list of potential witnesses, including victims, first-responders and detectives, among others.