Bangladesh, March 17 -- During the recent years, a growing body of research has raised troubling questions about the influence of extremist Islamist and jihadist networks within parts of the American educational landscape. While the United States has long prided itself on religious freedom and pluralism, critics warn that these same freedoms can be exploited by ideological movements seeking to reshape society from within. Nowhere is this concern more visible than in parts of the state of Texas, where investigators and policy experts say a network of Islamist-linked educational institutions has been steadily expanding its footprint.

The central concern is not religious education itself—America has thousands of faith-based schools of...