Kacy Corso, 34, of East Setauket, pleaded guilty in July 2026 to manslaughter and hindering prosecution in connection with a Suffolk County murder case.

The November 10, 2025, stabbing death of her ex-boyfriend, Christopher Millwater, 52, took place at the Stony Brook Yacht Club.

Background of the Stony Brook Murder Case

In December 2025, Corso and her then-boyfriend Victor Panebianco, 32, were indicted on second-degree murder charges for the slaying.

Millwater was found unconscious in the yacht club’s parking lot with two stab wounds to the chest.

Surveillance and audio evidence showed that Corso drove into the lot, parked in front of Millwater’s car, and then Panebianco exited her vehicle, chased Millwater, and stabbed him multiple times.

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Prosecution Position in the Murder Case

At her July 2026 plea hearing, Corso admitted to hindering prosecution as part of a plea deal and acknowledged her role in the incident.

Prosecutors are expected to seek a seven-year sentence because she fully cooperated with the case against Panebianco.

According to Law & Crime. Corso testified that she had “no plan” and only intended to cause serious physical injury, but she admitted to being present and involved in the confrontation.

Victim Was Harassing Corso

The case was marked by months of public hostility between Corso and the victim Millwater, including Facebook posts accusing him of harassment and “psycho” behavior.

Just two days before the murder, Millwater posted a cryptic message: “Plenty of time to rest when I’m dead.”

 Corso’s guilty plea marks a significant development in the case, with prosecutors aiming for a lengthy sentence in exchange for her cooperation, while Panebianco remains in custody facing the same murder charge.

Courtroom Details of the Murder Case

• Date of offense: November 10, 2025, around 3:42 a.m. www.suffolkcountyda.org
• Location: Stony Brook Yacht Club parking lot, 21 Shore Road, Long Island, NY www.suffolkcountyda.org
• Victim: Christopher Millwater, Selden, NY www.suffolkcountyda.org
• Defendants: Kacy Corso (pleaded guilty) and Victor Panebianco (still charged with murder) News 12 Networks+1
• Plea: Manslaughter and hindering prosecution News 12 Networks+1
• Sentencing: Scheduled for September 2026 News 12 Networks