A key witness in a federal investigation involving U.S. Rep. David Rivera failed to show up for an interview with prosecutors and the FBI one day after agents raided her Miami apartment and removed her computer, cellphone and other items.

Ana Alliegro’s whereabouts are a mystery — even to her lawyer.

“I still have not heard from my client. I have no idea where she is,” attorney Mauricio Padilla said Saturday before noon. “I have not talked to Ana since Wednesday.”

Prosecutors believe Alliegro played a key role as a go-between for Rivera and a former Democratic congressional candidate who might have broken campaign finance laws in his failed bid against a rival of the Republican congressman in the Aug. 14 primary.

Alliegro had been scheduled to testify Thursday before a federal grand jury in Fort Lauderdale, but Padilla worked out a deal to speak directly to lead prosecutor Thomas J. Mulvihill and two FBI agents.

According to Alliegro’s family, Padilla and Alliegro met Wednesday to prepare for the meeting. But sources say that Alliegro and Rivera met later that day.

Padilla, her family said, was to pick her up since she had no car and a suspended license. But her mother called her lawyer to say her father would drive her.

“Everything is fine,” said Alliegro’s mother, Agueda “Guedy” Alliegro. “I haven’t spoken to her, but she is OK.”

Miami police said Saturday morning that no one has filed a missing person's report.

Guedy Alliegro said investigators had previously met with her daughter to serve her a federal subpoena and arrest her for a suspended driver’s license.

“Who gets arrested for that?” she asked. “Ana is innocent. She really doesn’t have anything to offer. She is being harassed for political interests.”

The case definitely involves politics.

At issue: $46,000 in once-secret payments — many made with cash-stuffed envelopes — that candidate Justin Lamar Sternad used for mailers in his unsuccessful primary race against Joe Garcia, who now faces Rivera in the general election.

Sternad’s campaign finance disclosure reports initially gave no indication that he had paid for the mailers. He later amended the reports amid the FBI probe.

Investigators have focused on Alliegro because she acted as Sternad’s campaign manager. She may have first-hand knowledge of the source of the funds and whether Rivera was involved in funding the campaign of the political unknown, a part-time hotel worker.

The probe of Sternad and Rivera began last month after El Nuevo Herald and the Miami Herald reported Sternad may have violated federal campaign-finance laws by failing to disclose the expenditures or source of the funds on his Federal Election Commission reports.

The investigation — which involves a federal grand jury — picked up speed in recent weeks, with Rivera on the offensive, saying Herald reporters are in cahoots with Joe Garcia’s campaign and that no one from law enforcement has talked to him. Agents have been collecting documents, interviewing witnesses across the region.

Sternad’s pre-primary campaign report for the period ending July 25 showed he spent $11,262 for the entire campaign, of which $10,440 was for the state fee to qualify for the ballot in the newly drawn congressional District 26 primary race, which stretches from Kendall to Key West.