explosive devices

As the hunt intensifies to try to find who sent at least 10 potentially explosive devices to Democrats and critics of President Trump around the country, a second important question lingers: how exactly were the dangerous packages sent?

The FBI and the investigative arm of the U.S. Postal Service, the U.S. Postal Inspection Service, both declined Thursday to confirm to NPR how the packages reached the destinations at which they were intercepted.

Updated at 11:48 a.m. ET

The list of prominent people, eight and counting, who were sent suspicious packages reads like a Trump enemies list, politicians and Trump critics who are often targeted in his rally speeches and tweets.

Updated at 6:30 p.m. ET

Federal authorities expanded their nationwide search on Thursday for the person who sent a wave of suspected explosive devices to political nemeses of President Trump.

Ten devices addressed to eight targets have been intercepted or discovered, but no one has been hurt. It isn't clear whether or not the attack is over; the FBI said it can't rule out that more suspicious packages might still be moving through the mail.

President Trump began his rally in Wisconsin Wednesday night by condemning apparent explosive devices sent to former President Barack Obama, former Secretary of State Hillary Clinton and others, saying that "any acts or threats of political violence are an attack on democracy itself."

"No nation can succeed that tolerates violence or the threat of violence as a method of political intimidation," Trump said, pledging an "aggressive investigation" that will bring the suspects to justice "hopefully very soon."

Updated at 9:38 p.m. ET

At least seven suspicious packages containing what the FBI called potentially destructive devices have been sent since Monday to several leading Democratic Party figures and to CNN in New York, triggering a massive investigation.

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