11.   The investigation began a year ago after U.S. authorities were tipped off that large quantities of zirconium were being offered for sale on the black market.

12.   While it would be difficult to keep criminals from building bombs or amassing poison gas, intelligence-gathering could tip authorities before an attack, the report said.

13.   Singapore authorities tipped off Manila, leading to the arrest of Indonesian suspect Fathur Rohman al-Ghozi on Tuesday, they said.