A 73-year-old driver allegedly caused two fatal accidents on Wednesday morning.
Maricopa County Sheriff's deputies say a woman ran her SUV into bicyclist near Usery Pass and Bush Highway, at 9:18 a.m.
The bicyclist, a woman in her 50's, died at the scene.
Deputies say the 73-year-old immediately fled the area, ran a red light and T-boned a car near Ellsworth and McKellips.
The driver of the car, a 53-year-old man, also died at the scene. The accidents were just 6 minutes apart.
Deputies say the woman stopped and was airlifted to a hospital in critical condition with non-life threatening injuries.
MCSO detective Joaquin Enriquez says witnesses followed the woman after the hit-and-run and saw the entire situation play out.
"I saw such devastation -- I actually diverted my eyes when I saw everything. I have never seen such an amazingly devastating crash as that," said witness Mark Carpenter, a cyclist himself. "It's the worst crash I've ever seen."
Deputies don't know if impairment was a factor yet. They're looking into whether or not the woman has a medical condition. However, they haven't been able to make contact with her because of the severity of her injuries.
"We have not been able to start an investigation towards what actually happened out here," said Enriquez.
The names of the two deceased victims have not been released. The woman who caused the collisions is expected to survive and will be facing charges of hit-and-run at the very least.