Kacy Corso stood before a judge this week and admitted her role in a killing that began with a Facebook 'like' and ended with a man's final, horrified words to his killer.
The 34-year-old woman pleaded guilty to manslaughter and hindering prosecution on Tuesday for the November 2025 stabbing death of Christopher Millwater at the Stony Brook Yacht Club on Long Island's north shore. The 52-year-old victim was Corso's ex-boyfriend.
Background
Prosecutors say the murder traces back to a social media interaction. In the days before Millwater was killed, he had 'liked' one of Corso's Facebook posts, according to Fox News. That simple digital gesture would prove fatal.
"There was no plan," Corso told state Supreme Court Justice Timothy Mazzei during her plea hearing when asked about any premeditation. She claimed she simply drove the car that morning.
The attack unfolded in the early hours of Nov. 10, 2025, at 21 Shore Road. Surveillance footage and prosecutors' accounts paint a grim picture: After Corso parked her car in front of Millwater's vehicle, her then-boyfriend Victor Panebianco exited and approached. Millwater attempted to flee, driving around Corso's car toward the exit—but prosecutors say Corso rammed his vehicle.
After crashing, Millwater fled on foot. Panebianco chased him down with what authorities describe as some sort of object, stabbing him through his heart and lungs.
"You're stabbing me?" the frightened man asked his killer in those final moments, according to prosecutors.
The Charges
Corso pleaded guilty to manslaughter in the second degree and hindering prosecution. She agreed to fully cooperate with prosecutors as they build their case against Panebianco, who remains charged with murder in the second degree and faces up to 25 years in prison if convicted.
"She accepted responsibility," defense attorney Christopher Gioe said outside the Riverhead courthouse on Wednesday. "She had a very limited role in what happened in this case."
Video evidence shows that as Millwater lay motionless on the ground, Panebianco allegedly threatened to kill him and yelled at him to stay away from Corso before kicking him in the head, prosecutors said in their indictment announcement. Corso can also be heard yelling at Millwater during the attack.
"Shortly after Corso drove into the parking lot at the yacht club, Millwater pulled in and parked next to her," prosecutors wrote. "Corso then allegedly drove her car into his vehicle."
Police discovered Millwater around 3:40 a.m. and rushed him to Stony Brook University Hospital, where he was pronounced dead.
Key Takeaways
- Kacy Corso, 34, pleaded guilty to manslaughter and hindering prosecution for the death of her ex-boyfriend Christopher Millwater, 52
- The victim had 'liked' one of Corso's Facebook posts days before he was killed, prosecutors say
- Victor Panebianco, 32, remains charged with second-degree murder and could face up to 25 years in prison if convicted
- Prosecutors are likely to seek a seven-year sentence for Corso due to her cooperation agreement
- Surveillance footage captured Millwater asking his killer 'You're stabbing me?' as he was stabbed through the heart and lungs
- Corso is slated for sentencing in September while Panebianco's case continues
What's Next
Corso faces a September sentencing date where prosecutors are expected to recommend seven years behind bars—a reduced term in exchange for her cooperation against Panebianco. Her then-boyfriend's murder trial will proceed separately, with the state presenting surveillance footage and Corso's testimony as central pieces of their case.