Kimberely Stoll, 57, "suffered head trauma and never regained consciousness" and was pronounced dead just after 1 a.m. Tuesday, a close friend who's also a first responder told Daily Voice.
Stoll was on the back of the 2008 Harley Davidson that collided with a 2017 Jeep Wrangler in front of the Wells Fargo Bank on Lafayette Avenue around 9:45 p.m. Saturday.
The crash killed 49-year-old Kasey "KC" Checke, the owner-operator of KC's Kustom Exhaust and Auto Service on Franklin Turnpike in Ramsey.
The driver of the Jeep -- identified as Anthony Giannella, 25, also of Hawthorne -- wasn't injured.
Two ambulances and two paramedics responded along with police, the Passaic County Sheriff's Office Crime Scene Investigation Unit and the prosecutor's fatal accident investigations unit.
No official word had yet been released about charges or summonses.
In a release issued early Tuesday afternoon, Passaic County Prosecutor Camelia Valdes and Hawthorne Police Chief Richard McAuliffe said their agencies were still investigating the crash.
Meanwhile, Checke's family was still making arrangements for his funeral.
Boyd A. Loving contributed to this report.
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