<i>Weeks after Google hired him in 2007 to work on a global photo database called Street View, Mr. Levandowski, then 27 years old, registered a startup to sell a sensor system to Google for the same project, according to public records and former employees of both companies.<p>For the next four years, Mr. Levandowski split his time between his day job at Google and the startup, 510 Systems LLC, an hour away in Berkeley, Calif., where he directed employees to develop technology related to his Google projects, including self-driving cars, according to former 510 Systems employees.<p>After Google discovered the side business, instead of reprimanding Mr. Levandowski for a potential conflict of interest, it ultimately bought 510 Systems for about $20 million.</i>