Victor Panebianco’s August plea follows Kacy Corso’s earlier admission and leaves sentencing as the main remaining stage of the prosecution.
RIVERHEAD, N.Y. — The murder prosecution stemming from Christopher Millwater’s killing outside the Stony Brook Yacht Club has shifted from a potential two-defendant trial to two sentencing hearings after Victor Panebianco joined Kacy Corso in pleading guilty to first-degree manslaughter.
Panebianco, 32, entered his plea Aug. 11 before state Supreme Court Justice Timothy P. Mazzei, the latest major development in a case that began when Millwater was found fatally injured near the Long Island marina in November 2025. Panebianco is expected to be sentenced Sept. 22 to 25 years to life in prison, according to reporting based on the Suffolk County District Attorney’s Office. Corso, 34, had already pleaded guilty July 22 to first-degree manslaughter and hindering prosecution. Her sentencing is scheduled for Sept. 2, with a seven-year prison term expected.
The paired pleas mark a substantial change from December, when a Suffolk County grand jury indicted Panebianco and Corso on second-degree murder charges. Prosecutors initially said the two acted together in what District Attorney Raymond A. Tierney’s office described as a coordinated attack on Millwater, Corso’s former boyfriend. Both faced the prospect of murder trials. Instead, each has now admitted manslaughter, though the expected punishment for Panebianco is far greater than the sentence contemplated for Corso. The prosecution has said Corso agreed to cooperate with the state’s case, an important part of the disposition reached with her.
The case began before dawn Nov. 10, 2025. Suffolk County police said Millwater, 52, of Selden, was found injured in front of 21 Shore Road in Stony Brook at about 3:40 a.m. Officers and emergency personnel took him to Stony Brook University Hospital, where he was pronounced dead. Police initially released few details beyond saying he had been the victim of violence. In the days that followed, detectives built a case that would extend from surveillance cameras around the waterfront parking area to arrests in both New York and North Carolina.
Corso became the first of the two to be publicly charged in Suffolk County. Police announced her arrest on Nov. 20 and initially accused her of second-degree murder. Panebianco was in custody in North Carolina and was expected to be extradited. The district attorney’s office later said the pair were both living in King, North Carolina. Their connection to Millwater was personal: Corso had previously dated him, while Panebianco was described in court reporting as Corso’s boyfriend around the time of the killing.
When the indictment was announced Dec. 9, prosecutors provided a detailed account of the surveillance evidence. They said Corso drove into the Stony Brook Yacht Club parking lot with Panebianco in the passenger seat. Millwater arrived soon afterward and parked next to her. Corso then allegedly moved her vehicle in front of Millwater’s car. Panebianco got out and went toward him. Millwater managed to drive around Corso’s vehicle toward the lot’s exit, but prosecutors said Corso struck his car with hers before he got out and ran.
At that point, according to the state’s account, the case became a foot pursuit. Prosecutors said video showed Panebianco chasing Millwater while swinging an object. He caught up with him after Millwater fell or went to the ground. Authorities said Panebianco stabbed Millwater in the chest, causing fatal injuries. Prosecutors said Millwater could be heard asking, “You’re stabbing me?” and calling for help. The district attorney’s office further alleged that Panebianco threatened him, told him to stay away from Corso and later kicked him while he was motionless.
Corso’s alleged actions did not end with the collision. Prosecutors said her voice could also be heard during the confrontation and that, after Panebianco returned to her car, she drove away. Her later guilty plea resolved both a manslaughter count and a hindering-prosecution charge. At her July hearing, Corso reportedly told Mazzei that she intended to cause Millwater serious physical injury but denied that there had been a plan to kill him. When the judge asked what the plan had been, she answered, “There was no plan.”
That exchange placed a key distinction at the center of her plea: an admitted intent to participate in serious violence without an admission that she shared an intent to kill. Her lawyer, Christopher Gioe, said outside court that she had accepted responsibility and maintained that her role was limited. Prosecutors, however, had alleged from the outset that the positioning and ramming of her vehicle helped prevent Millwater from leaving. The plea agreement means a jury will not be asked to resolve competing interpretations of her intent under the original murder charge.
Panebianco’s later admission removed the possibility of a separate murder trial against him as well. His expected sentence is much longer. Subsequent reporting citing the district attorney said Panebianco is expected to receive 25 years to life after pleading guilty to first-degree manslaughter. Tierney said the plea could not remove the pain experienced by Millwater’s loved ones but would spare them a difficult trial. The prosecution credited Suffolk County homicide investigators and the Stokes County Sheriff’s Office in North Carolina for work connected to the case.
The investigation also drew public attention to social media activity among the people involved, though the available evidence does not establish that such activity caused the killing. Fox News reported that Millwater had “liked” a post on a Facebook account in Corso’s name only days before he died. The same account contained older material showing familiarity between Corso and Millwater. Because prosecutors have not publicly identified the Facebook interaction as a proven motive, the social media detail remains context rather than an established explanation for the confrontation.
Millwater’s death also carried a painful local dimension because the waterfront where he was killed was familiar to him. His sister told News 12 that Stony Brook was his favorite fishing location. The yacht club and nearby marina occupy a shoreline area associated with boating, fishing, restaurants and events rather than violent crime. A funeral home obituary identified Millwater as a Selden resident born Dec. 8, 1972. Reporting after his death also noted that he had posted about receiving encouraging news after treatment for cancer shortly before the homicide.
The two guilty pleas now leave the courts to determine the final sentences. Corso’s case will reach that point first on Sept. 2. Panebianco is due back before Mazzei on Sept. 22. Until those hearings occur, the seven-year and 25-years-to-life terms remain expected sentences rather than punishments already imposed. What is no longer unresolved is whether either defendant will stand trial for murder: both have now entered felony guilty pleas arising from Millwater’s death.
Author note: Last updated August 28, 2026.