MADISON, Wis. (AP) -- Thirteen Democratic lawmakers have sent Wisconsin Attorney General J.B. Van Hollen a letter requesting an investigation into the way Republicans handled the redrawing of political boundaries.

The request for a Department of Justice investigation was spearheaded by state Rep. Jon Richards of Milwaukee. A federal lawsuit over redistricting is scheduled to begin in Milwaukee later this month.

Richards says he is calling for the investigation following reports that most Republican lawmakers signed a legal agreement in which they promised to not comment publicly about redistricting discussions while new GOP-friendly maps were being drafted.

Richards says it appears the public's right to an open government have been violated.

Republican leaders say the agreements were signed to protect lawmakers from getting involved in lawsuits over the drawing of the maps.