Actor Robert De Niro is the latest person to be sent an explosive device like those sent earlier this week to Hillary Clinton, former President Barack Obama and former CIA Director John Brennan at CNN.
All of those to receive the mail bombs so far are prominent critics of President Donald Trump, but no motive is yet known for the sending of the explosives and no suspects have been identified.
In addition to the package sent to De Niro in New York City, a second device addressed to Democratic Rep. Maxine Waters of California was found in Los Angeles on Wednesday night. The first one addressed to Waters was intercepted earlier Wednesday by Capital Police in Washington, D.C.
The package to Waters is similar to the ones sent to Hillary Clinton and Barack Obama.
A similar-looking package may also have been sent to former Vice President Joe Biden, sources told ABC News. The package possibly sent to Biden is considered the eighth possible, packaged explosive in the domestic terrorism investigation.
The device addressed to De Niro was discovered early Thursday morning in New York's Tribeca neighborhood, ABC News confirmed. New York police removed the device in a bomb-containment vehicle.
Law enforcement officials told ABC News the contents of at least five of the packages sent this week resembled pipe bombs intended to maim or kill. The packages, bubble-wrap-lined manila envelopes with computer-printed labels, were sent to the FBI lab in Quantico, Virginia, for further analysis.
Several of the packages listed as a return address that of Rep. Debbie Wasserman Schultz, D-Fla., but her name was misspelled and the Democratic congresswoman, a former chairperson of the Democratic National Committee, is not considered to be involved in the sending of the devices.
The series of mailed explosives began Monday with the discovery of a pipe bomb in the home mailbox of billionaire George Soros, a Democratic supporter often criticized by right-wing groups.
"The FBI advises the public to remain vigilant and not touch, move or handle any suspicious or unknown packages," the FBI said in a statement Wednesday evening. "We ask anyone who may have information to contact the FBI."
