Prosecutors in Yavapai County announced Tuesday that they didn't find evidence to criminally charge Uber in the crash that killed a woman a year ago in Tempe.

But it is leaving possible criminal charges against the autonomous car's operator back in Maricopa County officials' hands.

Yavapai County Attorney Sheila Sullivan Polk's Office took the case at the request of Maricopa County Attorney Bill Montgomery after he cited a potential conflict of interest. Polk in a March 4 letter to Montgomery said her office would recommend that Tempe police further investigate to help Montgomery's office determine if any other charges should be filed against the driver.

A report the Tempe Police Department released in June revealed 44-year-old Rafaela Vasquez, the operator of Uber's self-driving vehicle, was watching "The Voice" via a streaming service when the autonomous car hit 49-year-old Elaine Herzberg on March 18 as she crossed Mill Avenue outside of a crosswalk with her bike.

Vasquez's eyes were focused on the phone screen instead of the road for approximately 32 percent of the 22-minute period, the report said. Tempe investigators later determined the crash would not have occurred if Vasquez had been "monitoring the vehicle and roadway conditions and was not distracted.”

But Polk said that wasn't enough to prosecute Uber.

"After a very thorough review of all the evidence presented, this Office has determined that there is no basis for criminal liability for the Uber corporation arising from this matter," Polk wrote in her letter. "Because this determination eliminates the basis for the MCAO conflict, we are returning the matter to MCAO for further review for criminal charges."

Specifically, Polk said in her letter, that police should have an expert analyst view the video of the crash.

"Specifically, we believe that an expert analysis of the video is needed," Polk wrote in her letter. "The purpose of the expert analysis is to closely match what (and when) the person sitting in the driver’s seat of the vehicle would or should have seen that night given the vehicle’s speed, lighting conditions, and other relevant factors."

A spokeswoman for Uber on Tuesday declined to comment on Polk's decision.

A spokeswoman for the Maricopa County Attorney's Office didn't immediately respond to an email from The Arizona Republic seeking comment.

$10 million claim

In February, Herzberg's daughter, Christine Wood, and Herzberg's husband, Rolf Ziemann, through their lawyers, filed a $10 million claim against Tempe.

They allege the city is liable for the accident because the median on Mill Avenue where the accident occurred "has a brick pathway cutting through the desert landscaping that is clearly designed to accommodate people to cross at the site of the accident."

Tempe tore out that X-shaped brick path in the median south of Curry Road in the fall, city spokeswoman Nikki Ripley confirmed. The brick walkway was replaced with rock landscaping and plants.

The change was made about the time the city was hit with the claim, which law firm Skousen, Gulbrandsen & Patience filed.

Shortly after the crash, the Glendale law firm Bellah Perez announced that it was representing the daughter and that they had reached a settlement with Uber for an undisclosed amount of money.

Uriel Garcia covers public safety issues in Arizona. Reach him at uriel.garcia@azcentral.com. Follow him on Twitter @ujohnnyg.