Woman To See Reduced Sentence For Cooperating Against Co-Defendant In Stony Brook Slaying Of Ex: Report

Kacy Corso, 34, received an offer of a reduced charge in exchange for cooperating with prosecutors, Newsday reported.

By Peggy Spellman Hoey, Patch Staff

Jul 22, 2026 2:56 pm EDT | Updated Jul 22, 2026 3:05 pm EDT

An East Setauket woman will likely get seven years in state prison after pleading guilty to manslaughter in connection with fatally stabbing her ex-boyfriend in Stony Brook, Newsday reported. (Google Maps)

RIVERSIDE, NY — An East Setauket woman will likely get seven years in state prison after pleading guilty to manslaughter in connection with fatally stabbing her ex-boyfriend in Stony Brook, Newsday reported.

Kacy Corso, 34, received the offer of a reduced charge in exchange with cooperating with prosecutors against her codefendant, Victor Panebianco, whom she said chased down Christopher Millwater, 52, of Selden, and stabbed him to death Nov. 10, the outlet reported.

Her defense attorney, Christopher Gioe, told the outlet that she "accepted responsibility" and "had a very limited role in what happened in this case.”

Corso was facing 25 years to life.

Patch has reached out to the DA's office and Gioe for comment.

For more from Newsday, click here.

Corso was charged in connection with the slaying of Millwater last November after he was found stabbed to death outside the Stony Brook Yacht Club.

Homicide Squad detectives charged Corso with second-degree murder for the stabbing death of Millwater, 52, of Selden, Suffolk police previously said.Corso and her then-boyfriend, Panebianco went to the yacht club, knowing Millwater would be there, and she used her car to block him from leaving, and then slammed it into him, News 12 reported, citing court documents.

Panebianco then stabbed Millwater multiple times, according to the outlet. Gioe previously told Patch that Corso "has vehemently denied any involvement in the stabbing incident and has not admitted to the charges."

"On her behalf, we have entered a plea of not guilty," he said. "We are committed to conducting a thorough investigation into this matter and defending our client zealously."

Millwater's sister previously told Patch that he had been fishing at the location where he was killed for around 30 years.

"He went there for peace, for tranquility," she said. "He did a lot of fishing there. I don't really know what else to say. He was just a wonderful person."