Grunwald, who is being held at the Salt Lake County jail, is charged as an adult with aggravated murder, a first-degree felony, and 13 other charges related to the Jan. 30 events in which the girl is accused of driving her pickup truck while her boyfriend allegedly shot and killed one police officer and wounded another.
Life in prison without parole is the maximum penalty the teen could face if convicted of aggravated murder. Because she is a minor, she is not eligible for the death penalty.
Grunwald is also charged with two counts of felony discharge of a firearm, two counts of attempted aggravated murder, and aggravated robbery all first-degree felonies along with charges of felony obstructing justice, failure to respond to an officer, possession or use of a controlled substance and lesser charges of felony discharge of a firearm, and misdemeanor criminal mischief and violation of operator duties after an accident.
While 27-year-old Jose Angel Garcia-Jauregui is accused of pulling the trigger, prosecutors claim the teen girl is just as responsible for killing Utah County Sheriff's Sgt. Cory Wride and wounding deputy Greg Sherwood.
"We think the culpability is such that she should be charged as an adult," Deputy Utah County Attorney Sam Pead said outside of court.
Prosecutors have said that the teen was an "active participant" in the alleged crimes.
Zabriskie painted a different picture of the teen.
"She's scared to death," he told KUTV 2News after Monday's hearing. "Being locked up in an adult environment with these serious charges is very traumatizing for her."
Several of Wride's family members attended the girl's initial appearance Monday but did not make any public statements afterward.
Garcia-Jauregui died at a hospital Jan. 31, the day after Juab County deputies ended the shooting spree by shooting and wounding him in the head.
Events began in Utah County at about 1 p.m. on Jan. 30, when Wride stopped his patrol car on State Road 73 about 5 miles west of Lehi to check on a pulled-over Toyota Tundra pickup truck driven by Grunwald.
Wride was sitting in his patrol car checking information given to him by Grunwald and Garcia-Jauregui when Garcia-Jauregui opened the back sliding window of the truck and shot and killed the officer. The girl then sped away from the scene, according to court documents, which rely on dash cam footage from Wride's vehicle.
Police believe Grunwald was still driving the truck when she encountered Sherwood in Santaquin.
As Sherwood was following the truck in his patrol vehicle, prosecutors allege the teen girl braked suddenly closing distance between her truck and Sherwood's vehicle and Garcia-Jauregui fired from the back window of the truck once more. Sherwood was struck once in the head.
The two continued south on Interstate 15, where the truck's tires were spiked. They commandeered another vehicle at gunpoint, but that vehicle was disabled by tire spikes south of Nephi, where Juab County sheriff's deputies arrested them after shooting and wounding Garcia-Jauregui, according to court documents.
According to charging documents, Grunwald and Garcia-Jauregui had been living together for several months at the teen's mother's home in Draper, and the couple planned to wed when Grunwald turned 18 in August.
The girl's grandmother, Renate Grunwald, told The Salt Lake Tribune that her granddaughter met Garcia-Jauregui six months before the fatal shooting while both were working at a meat packaging plant in Draper.
Renate Grunwald said when Garcia-Jauregui moved into Grunwald's home, it set off a conflict between her parents, Jerry Grunwald and Tori Grunwald. Jerry who is Renate's son wanted Garcia-Jauregui out of the house but, according to Renate, Tori wanted to let him stay.
Garcia-Juaregui was paroled in December 2012 from the Utah State Prison after serving five years of a one-to-15-year sentence for 2008 convictions for attempted murder and aggravated assault.
Tribune reporter Michael McFall contributed to this story.