David Rivera isn't in Congress any more -- the South Florida Republican lost his seat in the November election -- but he's still being linked to a criminal investigation in Florida.

That investigation took a turn Thursday, when the Miami Herald reported that a key suspect would change his plea to guilty.

From the Herald:

A key suspect in a criminal case tied to former Congressman David Rivera will officially switch his plea to guilty in three federal charges for illegal campaign activity.

Justin Lamar Sternad’s admission of wrongdoing next Wednesday will be another sign that he’s cooperating with the federal government in its investigation of Rivera.

The FBI jumped on Sternad’s trail after The Miami Herald and El Nuevo Herald began questioning his campaign finances and expenditures during the Democratic primary for the newly drawn Kendall-to-Key West District 26 congressional seat.

Sternad’s campaign finance reports showed he raised little money, yet he was able to produce and disseminate a dozen different types of pricey mailers — some of which attacked fellow Democrat Joe Garcia, the biggest threat to the Republican Rivera.

Former congressman David Rivera (R-Fla.). (AP Photo/Alan Diaz, File)

The implication, of course, is that Rivera may have somehow funded Sternad as a foil to Garcia, who defeated Rivera easily in November. Sternad turned himself in Friday to face charges related to the investigation.

Rivera, a close friend of Sen. Marco Rubio (R-Fla.) who once shared a house with the senator, was first elected to Congress in 2010 and served one term.