SAN FRANCISCO (AP) — A federal judge has unsealed an inflammatory letter in which a former Uber security specialist accused the ride-hailing service of corporate espionage. The letter alleges Uber dispatched a team of spies to steal its rivals' trade secrets and take other shady actions to thwart competition. The explosive allegations, released Friday, have reshaped a high-profile trial pitting Uber against Waymo, a Google spin-off accuses the ride-hailing service of stealing its self-driving car technology. The letter is also evidence in a criminal investigation being conducted by the U.S.