The arrest, two days after the letters were intercepted in mail-sorting facilities for the White House and the Capitol, was based on information collected "very early on" about who had sent the letters, said one of the officials.
"We can't say it is established fact," said one senior American official who was involved in the highly classified assessment, based on information collected by many of the country's 16 intelligence agencies.
The system will be based on information collected by health care providers on a massive scale.
The control action is generated based on information collected from a redundant, multi-sensors network.
They are based on information collected by the Higher Education Statistics Agency (Hesa) and the National Student Survey, published by Higher Education Funding Council for England (Hefce).
The survey also reported that growth had moderated, based on information collected on or before July 15.
Human rights organizations and Tibet advocacy groups have put out reports based on information collected through interviews.
The Fed survey is based on information collected from the Fed's 12 regional banks on or before July 19.
The analysis is based on information collected by hospitals in England, and is supported by in-depth case examples.
He added that the ability to track users, based on information collected from so-called cookies deposited on their computers, is "what helped the Internet grow so quickly".
The United Nations report is based on information collected in 39 developing countries by Demographic and Health Surveys, a program supported by the United States Agency for International Development and carried out by the polling organization Macro International.
