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Kosta Diamantis enters the U.S. District Court in Bridgeport during a break in his trial on October 16, 2025. Credit: Shahrzad Rasekh / CT Mirror

Konstantinos “Kosta” Diamantis, the former head of Connecticut’s school construction program, argued on Thursday and Friday that it was completely legal for him to accept tens of thousands of dollars in “fees” from a pair of school construction contractors.

But if that is true, prosecutors asked during a contentious cross-examination Friday, why did Diamantis try to keep the money he was accepting from Acranom Masonry and Construction Advocacy Professionals so secret?

During the eighth day of Diamantis’ ongoing federal corruption trial, prosecutors challenged Diamantis on a number of issues, including why he never reported the income he earned from those two companies on his federal tax returns or in his ethics filings with the state of Connecticut.

Diamantis told prosecutors that he didn’t have a “business relationship” with either company and thus didn’t need to report on his state ethics filings. And as for his tax returns, he told the jury that he would be amending his previous filings to account for the additional money he made between 2018 and 2021.

Diamantis’ time on the stand on Friday was far different from his experience testifying on Thursday, when his attorney Norm Pattis asked him questions about how he sought to save taxpayers money.

Assistant U.S. Attorney Jonathan Francis, who is leading the case against Diamantis, attempted to pick apart portions of his previous testimony.

With Diamantis willingly admitting that he received money from the two school construction companies, Francis focused on proving that Diamantis helped those two contractors on school construction projects or threatened to cut them out of projects if they didn’t pay up.

Francis was aided in that effort by the overwhelming amount of text messages, financial records and other hard evidence that prosecutors filed in the case.

The prosecutor pressed Diamantis over several hours to explain text messages and emails in which he directly intervened in the Weaver High School project in Hartford on behalf of Acranom. And he grilled Diamantis about one conversation in which he threatened to “find a new mason” on the Birch Grove project in Tolland if Acranom didn’t make payments to him.

“I will wait til Monday for him to give you 40,” he wrote.

“He has no idea who I am and my back to the wall,” Diamantis wrote in another message.

Under pressure from Francis, Diamantis agreed that he told Acranom’s leader that he would pull the company from the project.

But he suggested it was a hollow threat because he really didn’t have the power to hire or fire companies on school projects in Connecticut.

Throughout his two days of testimony, Diamantis maintained that he never used his public office for personal gain.

The checks he received from Construction Advocacy Professionals, Diamantis said, were for legal work he performed for the company.

And the cash he received from Acranom, he said, was payment for him to broker a relationship between Acranom and D’Amato construction, one of the largest construction firms in Connecticut.

That defense was challenged after Diamantis left the stand, however.

Pattis called Edward D’Amato Jr. to the stand, as one of Diamantis’ defense witnesses, but D’Amato repeatedly told the jury that Diamantis never brokered a meeting between his company and Acranom.

“I don’t recall a conversation like that, no,” D’Amato said.

But even before D’Amato testified, prosecutors had placed Diamantis on the defensive as they confronted him with his own text messages.

Francis ran Diamantis through a host of messages in which he discussed Acranom’s school construction contracts in Hartford and Tolland and, in the next breath, reminded the company’s executives of the money they owed him.

In one text message, Diamantis wrote: “I need 5 k desperately tomorrow from him, or anyone. I don’t care who;. I shouldn’t have to beg. He owes me 77 2 months ago.”

When asked about that message, Diamantis said he was referencing $77 that Sal Monarca, the owner of Acranom, owed him for a lunch.

Prosecutors also asked about a text exchange in which Diamantis instructed John Duffy, the vice president of Acranom, for money and then told him to “erase” their communications.

Diamantis was adamant, however, that he didn’t tell Duffy to delete the conversation because they were discussing his compensation.

“That’s not the context,” Diamantis said.

Throughout his hours of testimony, Diamantis and Francis verbally sparred. Francis tried to pin the defendant down to yes and no answers. And Diamantis sought to dodge some of the questions Francis posed.

The back-and-forth between the two men became so heated that, during a break, Pattis asked for a mistrial because of how Francis was handling the cross examination. He said the prosecutor was being too “theatrical” in his response to Diamantis’ answers.

U.S. District Judge Stefan Underhill denied that request to end the trial, but he asked Francis and Diamantis to “take the temperature down a notch.” And he warned that he didn’t want a “street fight” in his courtroom.

New evidence

As Diamantis’ time on the stand neared its end, prosecutors also dropped brand new evidence into the trial: text messages between Diamantis and his daughter, Anastasia.

Francis unveiled that evidence to the jury as he pressed Diamantis about whether he ever helped negotiate what Construction Advocacy Professionals paid his daughter as an administrative assistant.

Diamantis told the jury on Thursday that he had no role in negotiating what Antonietta DiBenedetto Roy, the owner of CAP, paid his daughter.

Anastasia Diamantis, center, enters the U.S. District Court in Bridgeport on October 16, 2025. Credit: Shahrzad Rasekh / CT Mirror

But the texts that Francis revealed showed Diamantis had multiple conversations with his daughter about what Roy would pay her. One of the exchanges suggested that compensation would be linked to how much CAP would make from a contract on the Birch Grove Elementary project in Tolland.

“I told (Roy) I expect you get percentage bonus,” Diamantis told his daughter. “I’m told don’t worry. I got Anastasia.”

At another point, Diamantis asked his daughter if she was satisfied after he “negotiated” another $1,500 for her.

“You happy,” he asked.

“Yes of course! I can pay my car taxes and a credit card!” his daughter responded.

“Great and more to come,” Diamantis said.

Diamantis said he couldn’t recall negotiating any compensation with CAP for his daughter.

Some of the other comments in the text messages, Diamantis added, were a “tongue in cheek” remark.

In 2024, Roy pleaded guilty to conspiring to bribe Diamantis on school construction projects.

Andrew joined CT Mirror as an investigative reporter in July 2021. Since that time, he's written stories about a state lawmaker who stole $1.2 million in pandemic relief funds, the state Treasurer's failure to return millions of dollars in unclaimed money to Connecticut citizens and an absentee ballot scandal that resulted in a judge tossing out the results of Bridgeport's 2023 Democratic mayoral primary. Prior to moving to Connecticut, Andrew was a reporter at local newspapers in North Dakota, West Virginia and South Carolina. His work focuses primarily on uncovering government corruption but over the course of his career, he has also written stories about the environment, the country's ongoing opioid epidemic and state and local governments. Do you have a story tip? Reach Andrew at 843-592-9958

Dave does in-depth investigative reporting for CT Mirror. His work focuses on government accountability including financial oversight, abuse of power, corruption, safety monitoring, and compliance with law. Before joining CT Mirror Altimari spent 23 years at the Hartford Courant breaking some of the state’s biggest, most impactful investigative stories.