An outspoken superfan of President Trump from South Florida was charged on Friday with sending explosive packages to at least a dozen of the President’s critics, apparently bringing to a close an attempted bombing spree that has gripped the country just ahead of the midterm elections.

The suspect, Cesar Altieri Sayoc Jr, 56, was arrested outside an auto parts store near Fort Lauderdale after a fast-moving investigation in which the authorities said they were able to pull a fingerprint from one of the bomb packages and collect Sayoc’s DNA from two others.

Sayoc, who seemed to be living out of a van in Aventura, Florida, was taken into custody on a day when four more explosive packages were found, including two intended for US senators, both Democrats.

A federal criminal complaint spells out his contempt for this week’s many bomb targets, noting that Sayoc’s van was slathered with images and slogans often found on fringe Right-wing social media accounts.

The complaint identifies a Twitter account that authorities said he used to rail against Democratic figures, and it notes that both his social media messages and the bomb packages used the same misspelling — “Hilary Clinton” — for Trump’s 2016 opponent.

Sayoc also posted frequently on Right-wing social media groups, the authorities said. On Facebook, Sayoc published photos of a Trump rally he attended during the 2016 presidential campaign.

He was wearing a red “Make America Great Again” hat.

Of the four bombs discovered on Friday, one was addressed to Senator Cory Booker, a New Jersey Democrat; another was sent to James R. Clapper Jr, a former director of national intelligence; and a third was intercepted before it reached Senator Kamala Harris, a California Democrat.

A fourth, found in a mail facility in California, was addressed to Tom Steyer, a prominent Democratic donor, Steyer said.

In all, Sayoc is believed to have sent at least 14 bombs to 12 targets, all of whom are regularly disparaged by the Right.

At a news conference in Washington, attorney-general Jeff Sessions announced that Sayoc had been charged with five federal crimes, including the interstate transportation of an explosive, the illegal mailing of explosives and making a threat against a former President and others.

The packages sent by Sayoc included photographs of his intended targets, each one marked with a red X, according to the criminal complaint.

When asked why Sayoc had sent the bombs to Democrats, Sessions said that he was not sure, but added that the suspect “appears to be a partisan”.

The FBI director, Christopher A. Wray, said that the bureau was still trying to determine if Sayoc’s bombs were “functional” but noted that they contained “energetic material” that could be dangerous. Wray said that the investigation was “active” and cautioned that there could be more bombs still undiscovered.

The criminal complaint against Sayoc was filed in US District Court for the Southern District of New York and detailed the five charges against him.

Sayoc is a registered Republican whose arrest record in Florida dates back to 1991 and includes felony theft, drug and fraud charges, as well as allegations that he threatened to use a bomb, public records show.