The Justice Department has recently been investigating Google over the fairness of its advertising business and online ad tools. Now, as reported by The Wall Street Journal, AT&T has decided to contribute to the investigation and , sharing its concerns with Google’s unfair advantage over the competition in the advertising sector.

In recent months, the department has been investigating the situation, asking questions to Google’s rivals and company executives, in regards to its third-party ad business and how it interacts with publishers and advertisers. However, Google had previously ...