In all, Sternad sent 12 mailers in the race — one of which savaged Garcia over his divorce by using a line of attack that originated with Rivera.

The owner of Rapid Mail, John Borrero, first told The Herald in early August that he had been paid in cash — a rarity in campaigns, which usually rely on checks so that a candidate can clearly show the source and amounts of his receipts and expenses. Borrero said that Alliegro paid for the mailers multiple times. All but $9,000 of the nearly $47,000 in work was paid in cash

In August, Borrero said that he turned over two of the envelopes that were in his trash can to Miami-Dade public corruption investigators. They turned the documents over to the FBI, when it opened an inquiry. Agents now have two more envelopes.

Sternad’s primary reports initially gave no indication that he could afford a dozen mailers.

The invoices were initially printed to the attention of Rivera for six Sternad mailers, ranging from fliers titled “Obamacare/Trayvon” to “Lamar for Congress,” records and interviews show. But Rivera demanded that his name be removed, so the invoices only read: “Lamar Sternad for Congress.”

Sternad’s initial reports showed he had loaned himself $11,262, most of which was spent on the state fee to qualify for the Democratic primary ballot. After repeated questions from The Herald, Sternad amended his financial disclosures to show he had loaned himself nearly $53,000 more than originally reported. Still, his reports never showed how he paid for the actual printing of the dozen mailers, which would cost tens of thousands of dollars more.

Sternad’s personal financial disclosures show he is a a part-time South Beach hotel worker who earned just $30,000 last year; he listed a one-third interest in a mutual fund valued at a maximum of $100,000. He derived no income from it last year, his disclosures show.

Sternad’s finances weren’t the only mystery — so was the level of sophistication of his mailers, which targeted slices of the electorate with specialized messages. They were good enough to earn him 11 percent of the vote.

Alliegro took credit for much of the work. FBI agents want to know exactly what she knew and when.

Alliegro’s mother, Agueda “Guedy” Alliegro, said Friday afternoon that she has not heard from her daughter in two weeks and neither have other family members.

“I am worried,” she said. “I know she is resting. We are praying for her.”

Guedy Alliegro said that law enforcement has not contacted her family, which hasn’t filed a missing-person’s report. She said she has no reason to think that her daughter would be cooperating with the FBI.

“Ana has done nothing wrong,” the mother said.