PROVIDENCE, R.I. (WPRI) — The Sabina Matos campaign filed a complaint with federal regulators Friday, accusing Democratic rival Aaron Regunburg of violating campaign finance laws and suggesting he illegally coordinated with a super PAC funded by his in-laws.

The complaint submitted to the U.S. Federal Election Commission focuses largely on the relationship between the Progress Rhode Island super PAC and Regunberg, who is running against Matos and 10 other Democrats to represent the 1st Congressional District.

Matos alleges the super PAC — which is funded entirely by Regunberg’s father-in-law and mother — failed to make timely reports to federal regulators. She also raises questions about whether Regunberg illegally solicited contributions from his father-in-law and then coordinated political messaging with the super PAC — which is illegal under federal campaign finance law.

“Given that the Super PAC’s sole purpose appears to be to support candidate Regunberg, it appears that the candidate’s family knew the intentions of the Super PAC before they made their contributions,” Matos campaign manager Brexton Isaacs wrote in the complaint. “This begs the question: did candidate Regunberg relay information to his family that they then used to guide the activities of a Super PAC supporting his election?”

The Regunberg campaign fired back. Campaign manager Matt DaSilva called the complaint a “ridiculous and unserious attack from a desperate candidate whose campaign has been dogged by ethical questions and is currently under criminal investigation.”

Matos has been under fire for weeks after local election officials and Rhode Island residents came forward saying signatures had been forged on the lieutenant governor’s nomination papers. The fraud allegations spurred the Board of Elections to review Matos’ signatures, ultimately concluding she still had more than enough validated signatures to remain on the ballot.

R.I. Attorney General Peter Neronha and R.I. State Police have launched a separate criminal investigation into the signatures, causing an ongoing political headache for the Matos campaign. The lieutenant governor and Regunberg are perceived frontrunners in the crowded race, although it’s unclear who’s jockeying at the top as the race has seen no public polling.

The federal complaint comes in the wake of a debate held Thursday at Roger Williams University where Matos challenged Regunberg on whether he’s been coordinating with the family super PAC.

She questioned Regunberg about whether he placed a so-called “red box” on his website, which is a way candidates try to skirt campaign finance laws that prohibit official coordination with super PACs. The boxes typically contain specific information on what the candidates are seeking in terms of ads, along with what voters blocs they’re trying to target.

During the debate, Regunberg told Matos he never had one on his website, which the Matos campaign is now calling a lie.

“Aaron Regunberg is getting himself in incredibly hot water by falsely claiming his campaign never had a ‘red box’ that signaled messaging and photos to his family’s Super PAC,” Isaacs said in a statement. “It’s just not true – and voters deserve to know the truth.”

On Friday, DaSilva acknowledged the photos detailed in Matos’s complaint were publicly available for some period of time, but have since been taken down.

He also pointed a finger at Matos, alleging she’s “been communicating with the super PACs supporting her, with Twitter messages literally spelling out target voter universes in clear violation of the spirit of noncoordinating laws.”

“This is just another example of the Matos campaign engaging in legally and ethically questionable behavior,” DaSilva said.

DaSilva was referring to an unusual tweet sent by Dan Sena, a Democratic operative who works with the Congressional Hispanic Caucus BOLD PAC, which supports Matos. As 12 News reported Aug. 3, the tweet used political jargon to spell out exactly how BOLD PAC planned to spend its $400,000 campaign outlay for Matos.

Early voting is already underway for the primary election scheduled for Sept. 5.