A bipartisan coalition of lawmakers is demanding to know how widespread the use of warrantless surveillance is within the Obama administration, after it became known that the Internal Revenue Service has quietly been using “cell-site simulator” technology to collect data from unsuspecting people.

In a Monday letter to all 24 federal agencies, the leaders of the House Oversight Committee said it wants to know which other agencies are using this technology, commonly known as “Stingray” technology that poses as cell phone towers. It was spearheaded by committee Chairman Jason Chaffetz, R-Utah, and Ranking Member Elijah Cummings, R-Md.