Reports that intelligence tying Syrian President Bashar Assad or his top lieutenants to an alleged chemical weapons attack last week is no “slam dunk” are delaying any U.S. response and are likely to stir even more dissent among members of Congress about launching air strikes into Syria.

Members of the U.S. intelligence community say there are serious holes in information they have gathered since the alleged chemical assault outside Damascus about who actually controls Syria’s chemical weapons stockpiles and there are doubts about whether Assad himself ordered the strike, according to an Associated Press report.