The Yavapai County Attorney said in a letter made public that there was "no basis for criminal liability" for Uber, but that the back-up driver, Rafaela Vasquez, should be referred to the Tempe police for additional investigation. Prosecutors' decision not to pursue criminal charges removes one potential headache for the ride-hailing company as the company's executives try to resolve a long list of federal investigations, lawsuits and other legal risks ahead of a hotly anticipated initial public offering this year. The crash involved a Volvo XC90 sport utility vehicle that Uber was using to test self-driving technology. The fatal accident was a setback from which the company has yet to recover; its autonomous vehicle testing remains dramatically reduced. The accident was also a blow to the entire autonomous vehicle industry and led other companies to temporarily halt their testing.