How the investigation into series of package bombs unfolded

NEW YORK (AP) -- A week of mail bombs started with a single suspicious package in a billionaire's mailbox. In the days that followed, at least a dozen more suspected explosive devices were found, all of them targeting high-profile critics of President Donald Trump. On Friday, as still more suspected devices were being investigated, authorities arrested Cesar Sayoc, 56, of Aventura, Florida, who they say had used social media and the exterior of his van to rail against Democrats and CNN.

Here are key moments in the investigation, according to a criminal complaint filed by prosecutors Friday.

BETWEEN OCT. 18 AND OCT. 20

-- Packages addressed to former President Barack Obama, former Secretary of State Hillary Clinton, actor Robert De Niro, former Vice President Joe Biden and Rep. Maxine Waters are processed at a U.S. Postal Service center in Opa-locka, Florida, and begin their journeys to places around the country. Each is a padded, manila envelope with six American flag stamps, containing a PVC pipe, cap, clock, battery, wires and material investigators said could have exploded with heat or friction.

MONDAY, OCT. 22

-- A package containing an apparent pipe bomb is delivered via the U.S. mail to an estate belonging to billionaire liberal activist George Soros in Bedford, New York, about 30 miles north of New York City. It goes to a house on the property where Soros' former wife lives.

-- On his Twitter account, Sayoc retweets a post saying, "The world is waking up to the horrors of George Soros."

TUESDAY, OCT. 23

-- The package addressed to Clinton's home in Chappaqua, New York, is delivered to a residence used by her staff.

-- The package addressed to Obama is intercepted at a post office box in Washington, D.C. Along with the explosive, it contains a photograph of Obama marked with a red "X."

WEDNESDAY, OCT. 24

-- A package containing an explosive is found in the mailroom at CNN's Manhattan offices. It is addressed to former CIA director John Brennan and contains a photograph of him marked with an "X."

-- A package intended for former Attorney General Eric Holder is returned to sender and ends up at the Sunrise, Florida, office of Democratic Rep. Debbie Wasserman Schultz, which is listed as the return address on all the packages.

-- Two packages addressed to offices maintained by Waters, a California Democrat, are discovered in Los Angeles and Washington, D.C. One of them contains a photo of Waters marked with a red "X." Investigators later reveal that one of the Waters packages also contained a latent fingerprint and a possible DNA sample linked to Sayoc.

-- Sayoc posts another Twitter message vilifying Soros.

-- Trump says, "Acts or threats of political violence have no place in the United States."

THURSDAY, OCT. 25

-- A package addressed to Biden and initially sent to an assisted living facility and a second package unsuccessfully delivered to his home are recovered at postal centers in Delaware.

-- A retired New York City police detective working in security for De Niro alerts authorities to a package, resembling the others, in the mailroom at the actor's Manhattan film company.

-- Thursday night, authorities flock to the postal sorting facility in Opa-locka, Florida.

FRIDAY, OCT. 26

-- 9:19 a.m.: Trump complains in a tweet that the package bombs are hurting Republicans. "Republicans are doing so well in early voting, and at the polls, and now this `Bomb' stuff happens and the momentum greatly slows - news not talking politics. Very unfortunate, what is going on."

-- 8 a.m.: A worker at a midtown Manhattan postal facility alerts authorities to a package intended for former Director of National Intelligence James Clapper and addressed to CNN's New York City offices.

-- 8:45 a.m.: The FBI says a package addressed to Sen. Cory Booker, D-N.J., is recovered at the mail processing center in Opa-locka, Florida.

-- 11:15 a.m.: The Justice Department arrests Sayoc at an auto parts store in Plantation, Florida. Authorities say his van is covered with political images, including criticism of CNN.

-- 2:15 p.m.: A package like the others, addressed to Sen. Kamala Harris, D-Calif., is intercepted at a Sacramento mail facility.

-- 2:30 p.m.: Billionaire liberal activist Tom Steyer says a suspicious package addressed to him was intercepted at a Burlingame, California, mail facility. The FBI later confirms it's similar in appearance to the others.