Photos of the van showed that one of the stickers depicted a heroic Mr. Trump standing in front of flames and the American flag. Another was of Mrs. Clinton’s face in the cross hairs of a rifle scope. A third said: “CNN Sucks.”

“It struck me because of the crazy, conspiratorial stickers covering the windows,” said David Cypkin, a documentary film producer who until recently lived in Aventura and often noticed the van. “It was unsettling, and also it seemed to be occupied. Sometimes the door would be ajar or a window would be open, which indicated to me that maybe somebody was living in the van.”

The criminal complaint against Mr. Sayoc was filed in Federal District Court in Manhattan, where he will be prosecuted. Five of the bombs sent this week fall under the jurisdiction of federal prosecutors in Manhattan.

Mr. Sayoc is expected to appear before a judge in Florida on Monday.

A lawyer from the Federal Defenders office in Manhattan, Sarah Baumgartel, was assigned to represent him. “We hope that he will be presented in court and brought to New York expeditiously so that the case can proceed,” Ms. Baumgartel said.

For months now, Mr. Trump has been attacking the F.B.I., ridiculing its officials and damaging morale at the bureau.

The swift arrest on Friday was a public win for Mr. Wray, the F.B.I. director, and a reminder of his agency’s effectiveness.