Kacy Corso sentenced to 7 years for fatal attack of ex-boyfriend at Stony Brook Yacht Club

The mother of Christopher Millwater accused the duo responsible for her son's death of taking a victory lap past her home after committing the overnight attack outside the Stony Brook Yacht Club last November.

Mary Ellen Millwater, of Selden, said at the sentencing of her son’s former girlfriend that she was awakened shortly after the 3:30 a.m. attack to the sound of a "horn blaring" as a car drove down her street.

"In my heart I know what I witnessed was a celebratory ride past my home," Millwater said at the sentencing of Kacy Corso.

Corso, 34, of East Setauket, was sentenced under a plea agreement to 7 years in state prison for manslaughter. She admitted in July to driving her new boyfriend, Victor Panebianco, to Millwater’s favorite fishing spot and crashing into his vehicle before Panebianco stabbed him to death.

Millwater’s family members expressed disappointment in Corso’s sentence but said they believed a plea deal was the only sure path to a conviction, since proving the couple had planned to kill Millwater would have been difficult.

"Losing this full trial would have pushed me past my limit," Millwater told state Supreme Court Justice Timothy Mazzei in Riverhead.

Panebianco, 32, of North Carolina, who also pleaded guilty to manslaughter, was sentenced to 25 years in state prison Tuesday.

Corso apologized to the victim’s family Wednesday, acknowledging they had treated her and her children kindly while she was in a relationship with Millwater, 52, of Selden.

"It should have never happened," Corso said in a voice so soft Mazzei asked her to speak up.

Corso admitted in July to driving on Nov. 10 with Panebianco from North Carolina, where they had been living, to the yacht club, where Millwater was known to fish. She said she drove her Honda Civic into Millwater’s vehicle so Panebianco could chase him down and stab him. She said they were intent on injuring the victim.

Prosecutors had said Corso was in a long-term romantic relationship with Millwater that ended badly. Before the stabbing, both Corso and Panebianco accused Millwater of harassing her in posts on Facebook.

At her arraignment in December, Assistant District Attorney Sheetal Shetty said police-worn body cameras captured Corso saying she was afraid of what she might do to Millwater.

Video surveillance showed the couple going to the yacht club and Corso using her car to block Millwater's vehicle in the parking lot while Panebianco ran toward him with a knife shortly after 3:30 a.m. Corso remained in the car.

Millwater began running from Panebianco, who prosecutors said was chasing him with a knife, while Millwater was yelling for help.

The victim’s sister, Corinne Millwater, said Wednesday that Corso will serve a "measly" seven years while her family will feel their loss forever.

"I have to learn to live without him, which is a life sentence," she said.

Niece Serenity Verderosa called the 7-year sentence "far too lenient."

"I’ll always believe she was more involved in my uncle’s killing than she will ever admit," Verderosa told the judge, who reminded her the sentence was the result of a plea bargain, not one he handed down at his own discretion.

Prosecutors have said Corso and Panebianco left the state for North Carolina after the killing and that both the car and murder weapon were recovered in North Carolina.

By Grant Parpan

grant.parpan@newsday.com@GrantParpan

Grant Parpan covers Suffolk County courts and federal courts for Newsday. A Long Island native, he joined Newsday in 2022.