The Reichstag fire was blamed on Communists in Germany. However, the timing of the fire just four weeks after Hitler's installation as leader couldn't have been a coincidence. Hitler used the incident to suspend civil rights in Germany to allow him and his men to hunt down the alleged Communists who perpetrated the fire. The rest is, unfortunately, history as Hitler continued human rights abuses until his death in April 1945.
I believe that the Nazis caused the Reichstag fire because it solidified them in ruling Germany. Although it is not known for sure who was all involved in the fire, I do believe that the Nazis were behind the fire. I think they staged the fire to blame their opponents in order to gain the upper hand in politics.