Testing would gauge the functionality of the devices, check the type of pipe used and examine the powder to determine whether it is high explosive, low explosive or a chemical substance intended to be dispersed when the devices were triggered, Barry said. Investigators are homing in on a postal facility in Opa-locka, Florida, where they believe some of the packages originated, another official said.The officials spoke on condition of anonymity because they were not authorized to discuss the ongoing investigation by name.Homeland Security Secretary Kirstjen Nielsen, in an interview Thursday night with Fox News Channel, acknowledged that some of packages originated in Florida.New details about the devices came as the four-day mail bomb scare spread nationwide, drawing investigators from dozens of federal, state and local agencies in the effort to identify one or more perpetrators.The targets have included Obama, Hillary Clinton, CNN and Rep. Maxine Waters of California. Police have investigated multiple unattended packages in recent days and are urging the public to report anything that could be dangerous. Attorney General Jeff Sessions cancelled a planned trip to Louisville, Ky., Friday to ensure that all federal law enforcement resources, including the aircraft and personnel required for the attorney general's travel, were being devoted to the investigation. Suspicious packages addressed to New Jersey Sen. Cory Booker and former National Intelligence Director James Clapper - and similar in appearance to pipe bomb devices sent to other prominent Democrats - have been intercepted, the FBI said Friday, as investigators scrambled from coast to coast to locate the culprit and motives behind a bizarre plot aimed at critics of President Donald Trump.The discoveries brought to 12 the total number of devices addressed in recent days to Democratic figures including former President Barack Obama, former Vice President Joe Biden and Hillary Clinton.The FBI said the package to Booker was intercepted in Florida. Senator Kamala Harris and billionaire Democratic activist Tom Steyer were intercepted Friday in what authorities called a Florida man’s plot to mail more than a dozen pipe bombs to politicians and public figures critical of President Trump. It was addressed to former Director of National Intelligence James Clapper, according to law enforcement sources.Robert De Niro said in a statement: "I thank God no one's been hurt, and I thank the brave and resourceful security and law enforcement people for protecting us. "CNN didn't immediately respond to messages seeking comment before business hours Friday.The list of bombing targets spread from New York, Delaware and Washington, D.C., to Florida and California.The explosive devices were packed in envelopes with bubble-wrap interiors bearing six American flag stamps and the return address of Florida Rep. Debbie Wasserman Schultz, the former chairwoman of the Democratic National Committee.The bombs seized Wednesday were about 6 inches (15 centimeters) long and packed with powder and broken glass, according to a law enforcement official who viewed X-ray images. An earlier package had been sent to former Obama CIA Director John Brennan in care of CNN in New York.Investigators were analyzing the innards of the crude devices to reveal whether they were intended to detonate or simply sow fear just before Election Day.Law enforcement officials told The Associated Press that the devices, containing timers and batteries, were not rigged like booby-trapped package bombs that would explode upon opening. More: How to identify a suspicious package, and what to do with it
• Former CIA Director John Brennan, sent to CNN’s offices in New York City
• Florida's Democratic Rep. Debbie Wasserman Schultz (a package discovered at her office was addressed to former U.S. Attorney General Eric Holder)
• Billionaire George Soros, in the mailbox at his home in Bedford, New York
• Former Vice President Joe Biden; two packages were intercepted at Delaware postal facilities
• Former Director of National Intelligence James Clapper in New York

Will there be more suspicious packages?
Authorities are also investigating a packages addressed to former Director of National Intelligence James Clapper and billionaire Tom Steyer.