Yavapai County prosecutors said today that Uber is not criminally liable for a crash last year when one of its self-driving cars fatally struck a pedestrian in Tempe, Arizona.

The autonomous SUV, which had a backup driver behind the wheel, collided with Elaine Herzberg while she was walking across the street. She later died as a result of her injuries. After the crash, Uber suspended its self-driving test program on public roads for nine months.

In a letter to the Maricopa County Attorney, prosecutor Sheila Polk wrote that based on its investigation, the Yavapai County Attorney’s office had determined that a video of the collision “likely does not accurately depict the events that occurred.” While “there is no basis” for Uber to be held criminally liable, Polk recommended the case be referred to Tempe police to collect further evidence related to the vehicle’s backup driver, Rafaela Vasquez. Police said last year Vasquez had been watching streaming videos on her smartphone while sitting behind the wheel.

Polk wrote that her office believes an expert analysis of the video is necessary 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.”

Though Uber was found not criminally liable in the Tempe crash, The Information reported in December that an Uber manager had sent executives an email to warn about safety issues in its autonomous vehicle unit less than a week before Herzberg was killed.

TechCrunch has contacted Uber for comment.