The inquiry's investigations have included the May 2012 Houla massacre. Its preliminary report was published in June 2012. The report noted that the commission's investigation was significantly hindered because they had not been allowed access to Syria. Based on the available evidence, the commission did not rule out any of three possible perpetrators but said it was unlikely that anti-government fighters were responsible. In an August 2012 report, following continued investigations focusing on identifying the perpetrators, the commission concluded there was a reasonable basis to believe the perpetrators were aligned to the Syrian government. The report said a "lack of credible information supporting other possibilities" bolstered this conclusion.