DINA CAPPIELLOWASHINGTON (AP) ¿ The Justice Department has launched an investigation into whether former Interior Secretary Gale A. Norton illegally used her position to steer lucrative oil leases to Royal Dutch Shell PLC, the company she works for now, officials with both departments confirmed to The Associated Press. The criminal investigation is focused on a 2006 decision by the Interior Department to award three oil shale leases on federal land in Colorado to a Shell subsidiary. Oil from the leases could eventually earn the company hundreds of billions dollars. Investigators are looking into whether Norton, named by President George W. Bush to run the agency in 2001, violated a law that bars federal employees from discussing employment with a company if they are involved in a decision that could benefit that company. Months after granting the leases to Shell, Norton left the agency. Shell later that year hired her as an in-house counsel for its unconventional fuels division, which includes oil shale. Justice Department and Interior investigators also are trying to determine if Norton violated a broader federal "denial of honest services" law. Under the statute, government officials can be prosecuted for violating the public trust for directing government business to favored firms.