CLEARWATER, Fla. (Court TV) — An Ivy League-educated surgeon, representing himself in court, told a prosecutor to “shut the hell up” on Thursday after accusing the attorney of interfering in his case.
Tomasz Kosowski appears in court on Oct. 8, 2026. (Court TV)
Tomasz Kosowski, 47, was convicted after acting as his own attorney on a charge of first-degree murder in the death of attorney Steven Cozzi, 41. Cozzi represented clients Kosowski had sued when he disappeared in 2023. At trial, prosecutors presented surveillance video, DNA evidence, phone records and witness statements that showed the defendant had killed the victim in a bathroom at his law office before taking the body out of the building in a cart, loading it into a pickup truck and disposing of it in a dumpster.
Kosowski waived his right to a jury for both his trial and punishment. Judge Joseph Bulone convicted the defendant and is now tasked with deciding whether he should be sentenced to death. Bulone previously found that prosecutors proved Cozzi was killed for financial or pecuniary gain and that it was cold, calculated and premeditated. Bulone said prosecutors did not prove a third aggravating factor that the crime was heinous, atrocious or cruel due to the absence of the victim’s body and specific forensic details that would show how he was killed.
Kosowski returned to court on Thursday for a Spencer hearing, which is a final opportunity for a defendant to present mitigating evidence in a death penalty case before the judge imposes a sentence. Kosowski, still representing himself, again declined to present any evidence on his own behalf.
The defendant raised two issues he wanted to discuss: the return of his property from the state and a request to review all communications prosecutors had with his previous defense counsel. When prosecutors explained that Kosowski’s property issue was not yet “ripe” because the case had not been fully adjudicated, Kosowski countered: “It’s my stuff.” Bulone denied the motion.
Kosowski tried to demand access to communications between his first defense attorney, Bjorn Brunvand, and the prosecution team in the case, suggesting that prosecutors had forced Brunvand to withdraw in 2025 — when his trial was initially scheduled to begin — by sharing “private” videos of the defendant talking to his mother in which the two disparaged his legal team. “What did you think was going to happen two weeks before trial, listening to private conversations between my mother and me about Mr. Brunvand’s poor performance? What was his intent to do that two weeks before the trial?” Kosowski said Thursday. “It’s simple. It’s really, really simple. It’s an evil man speaking out of an evil heart, trying to poison the relationship, my relationship with my lawyer. That was the sole reason he did that. He’s trying to hide behind… he’s trying to masquerade, saying ‘I was so virtuous,’ ‘You know, I did not want that to happen.’ If you didn’t want it to happen, then why don’t you just shut the hell up?”
Prosecutor Nathan Vonderheide defended his actions, saying he gave the defense team recordings of Kosowski’s jail conversations with his mother to prevent arguments about ineffective assistance of counsel on a potential appeal.
Bulone denied that motion as well.
Because Kosowski refused to present any mitigating evidence on his own behalf, Bulone appointed special counsel to deliver mitigation. John Nohlgren focused his presentation on the defendant’s lack of criminal history.
Kosowski, Nohlgren said, was born in Poland in 1979 and emigrated to the United States in 1986. He graduated with degrees in music and biochemistry from the University of New Mexico before attending Dartmouth Medical School from 2002 to 2007, where he also earned an MBA. At Dartmouth, Kosowski served as class president and captain of the university’s ice hockey team.
As an adult, Kosowski made “major contributions” to the medical community in research and publications, Nohlgren said. “His various publications don’t just show contributions to cosmetic procedures, which some of them are related to cosmetic procedures, but they also include contributions to society’s knowledge on cleft palates, lung transplants, cancer research, schizophrenia and cardiac surgery,” Nohlgren said. “And these issues, Your Honor, are things that are paramount in our society’s health concerns. And his contributions will endure after whatever the court imposes at this point and be expounded upon and hopefully they will continue to aid the medical and scientific communities.”
Nohlgren acknowledged that regardless of the sentence, Kosowski’s medical career is over: “The only doc he’s going to be is a DOC number,” he said. But Nohlgren urged Bulone to consider a sentence of life without parole to allow Kosowski to “be a positive force in his environment. He has the capacity to be a teacher, a peacemaker and a leader to those in prison who are not so fortunate to possess his intellect, his education and his talents.”
Kosowski had no spouse or children, Nohlgren said, but before the defendant’s arrest, he was a “proud dog parent” to dachshunds Gibson and Rigby.
Bulone said he would announce Kosowski’s sentence at a hearing on Nov. 20.
