The Federal Trade Commission hired a top Washington litigator to run its antitrust investigation of Google Inc., signaling that the agency might be preparing a lawsuit against the world's largest search engine.

The FTC is bringing in Beth Wilkinson, who is known for winning the death sentence against Oklahoma City bomber Timothy McVeigh. Wilkinson, 49, has never lost a case.

Google disclosed in June that the FTC had opened a broad antitrust investigation of its business practices. The FTC is focusing on whether Google unfairly ranks search results to favor its own businesses and whether it increased advertising rates for competitors, people familiar with the probe told Bloomberg News at the time.

The agency also is examining whether the Mountain View, Calif., company is using its control of the Android mobile operating system to discourage smartphone makers from using rivals' applications, the sources said.