"On the evidence currently available, it was not possible to reach a finding about the chemical agents used, their delivery systems or the perpetrators," the team probing human rights violations in Syria said in its latest report on Wednesday.
It was clear however that "the majority of casualties result from unlawful attacks using conventional weapons," the Commission of Inquiry on Syria said in a statement.
But wait, there's more. BBC News is reporting that U.N. Sec-Gen Ban Moon now says that a report due next week will "overwhelmingly" confirm that chemical weapons were used in Syria last month.
Mr Ban said the UN findings would be "an overwhelming report that chemical weapons were used".
Mr Ban made no comment on blame but did say that Syrian President Bashar al-Assad had "carried out many crimes against humanity".
"Therefore, I'm sure that there will be surely the process of accountability when everything is over," Mr Ban said.