He reiterated that he expects to conclude the investigation by the end of the year.
The agency is investigating whether Google manipulates its search results to ensure that its own services, such as YouTube, Google Maps and Google Shopping, appear above those of its rivals.
Google's competitors argue that the company shouldn't be allowed to use its dominant search engine — which has about a 65 percent market share — to stifle competition.
The company says there is nothing unfair about its search rankings. Even if the results did boost Google products, the company says, it wouldn’t be illegal.
Leibowitz declined to say whether he thinks the case is similar to the Justice Department's suit against Microsoft in the late 1990s.
"We will leave that for other people to judge down the road," he said when pressed on the Microsoft comparison by host Peter Cook. "But again, one of the great things about our agency is we sit around, we talk. We meet with parties always and we try to come to the right resolution, and I believe we will do that and we will do it in a bipartisan manner in a way that protects American consumers and allows businesses — including Google which has done terrific things for consumers — to thrive."