Rebecca Koster, a 24-year-old home health aide from Medford, New York, was murdered in the early morning hours of December 4, 2009, after a night out at a Long Island bar. Evans Ganthier, a man she met that night, dismembered and burned her body in Connecticut, then used her phone to send taunting messages to her family. A Suffolk County jury convicted him of second-degree murder in 2013, and he was sentenced to 25 years to life. In August 2025, a federal judge vacated that conviction on Confrontation Clause grounds and ordered a new trial. The state has appealed, and the Rebecca Koster murder case remains open.
The Night Rebecca Koster Disappeared
Koster, a 2003 graduate of Patchogue-Medford High School, worked as an in-home aide for autistic children and geriatric patients.16abc.com. LI Man Charged in Cell Taunt Slay On the evening of December 3, 2009, she went out with friends to the Butcher Boys Bar and Grill in Holbrook. Her boyfriend, Dan Mayor, and two female friends said they dropped her at home around 3:30 a.m.2CBS News. Rebecca Koster’s Killer Cut Out Her Tattoo, Then Sent Taunting Texts to Family, Says NY DA By 6:00 a.m. she was gone.3ABC7. Police Identify Burned Body as Missing LI Woman
Ganthier, 30, from the Port Jefferson Station area, had also been at Butcher Boys. Surveillance video placed him at the bar talking to women in the early morning hours of December 4.4Newsday. Homicide Detective Testifies How Suspect’s Story Evolved Phone records showed Koster called him shortly after 3:30 a.m.5Newsday. Detective Testifies in Ganthier Murder Trial Ganthier eventually admitted to police that he picked her up at her home that morning. The two did not appear to have a prior relationship.
The Body on Jeremy Hill Road
Around 7:23 p.m. on December 4, a 911 caller reported a brush fire on Jeremy Hill Road near Mystic Road in North Stonington, Connecticut.6Connecticut DESPP. State Police Investigate Death Ruled a Homicide – Victim Identified Responders found burning human remains on the side of the road. The body had been wrapped in a blanket and beheaded. The victim’s fingers, toes, ears, nose, hair, and a butterfly tattoo on her back had been removed.2CBS News. Rebecca Koster’s Killer Cut Out Her Tattoo, Then Sent Taunting Texts to Family, Says NY DA Connecticut and Suffolk County investigators worked jointly to identify her. Koster’s parents were notified on December 9.3ABC7. Police Identify Burned Body as Missing LI Woman
The Text Messages
In the days after the killing, someone used Koster’s cell phone to send text messages to her family. One, sent at 11:40 p.m. two days after the body was found, read: “Dan has me tied up in a basement somewhere in Commack.” Another, to Koster’s mother, said: “Don’t tell Dan or he’ll kill me.”7NBC New York. Cops Arrest Alleged Killer Whose Texts Tortured Victim’s Family Prosecutors said the messages were meant to suggest Koster was still alive and to point suspicion at her boyfriend. Dan Mayor was never named a suspect and was never charged. When Koster’s family went to his home after receiving the texts, they found him already speaking with police.2CBS News. Rebecca Koster’s Killer Cut Out Her Tattoo, Then Sent Taunting Texts to Family, Says NY DA
Arrest and the Evidence Against Ganthier
Ganthier was arrested on February 8, 2010,8Connecticut DESPP. Suffolk County Police Make Arrest in North Stonington, Connecticut Death and arraigned the next day in Central Islip, where he pleaded not guilty to second-degree murder and was held without bail.9New York Post. LI Man Charged in Cell Taunt Slay
At trial in Suffolk County Court, prosecutors presented surveillance video of Ganthier and Koster together at Butcher Boys and of Ganthier on a ferry from Port Jefferson to Bridgeport the following morning.10Newsday. Graphic Details in Murder Case Repel Possible Jurors Blood matching Koster’s DNA was found on both sides of the center console and under the driver’s seat of his car.11Newsday. Prosecutor: Defendant Is ‘Dumbbell’ Who Killed Woman Detective Phillip Frendo testified that Ganthier’s account shifted over multiple interrogations: first denying he had been out, then acknowledging meeting women at bars, then admitting he picked Koster up and disposed of her body.4Newsday. Homicide Detective Testifies How Suspect’s Story Evolved
Ganthier’s version, offered through defense attorney William Keahon, was that Koster began gagging in his car, then tripped over dumbbells in his garage, hit her head, and died while he was driving her to the hospital. He said he panicked, took the ferry to Connecticut, and set the remains on fire. Keahon called his client’s conduct “despicable” but argued he was not the killer.4Newsday. Homicide Detective Testifies How Suspect’s Story Evolved
The autopsy was central to the dispute over cause of death. Dr. Ira Kanfer of the Connecticut Office of the Chief Medical Examiner performed it on December 5, 2009, and found that Koster died from a stab wound to the abdomen that pierced the left lobe of her liver, with roughly 200 cc of blood in her abdominal cavity.12GovInfo. Ganthier v. Superintendent, Green Haven Correctional Facility Kanfer did not testify. In his place the prosecution called Dr. Harold Wayne Carver, the recently retired Connecticut chief medical examiner. On cross-examination Carver acknowledged that the autopsy had “shortcomings,” that Kanfer had not documented the path of the knife wound or measured the depth of the liver injury, and that the findings were technically consistent with either a stab wound or an abrupt fall.13Newsday. Stab Wound to Liver Detailed in Ganthier Murder Trial
Conviction and Sentence
On August 29, 2013, a Suffolk County jury found Ganthier guilty of second-degree murder.14Newsday. Evans Ganthier Found Guilty in Stabbing Death of Rebecca Koster On September 30, 2013, he received the maximum sentence of 25 years to life in prison.15News 12 Long Island. Evans Ganthier Gets Maximum 25 Years to Life for Murder of Becky Koster
Why the Conviction Was Vacated in 2025
Ganthier lost his direct appeal in June 2021, when the New York Appellate Division, Second Department, rejected his three claims, including his argument that admitting the autopsy report through surrogate testimony violated the Sixth Amendment.16FindLaw. People v. Ganthier He then took the confrontation issue into federal court through a habeas corpus petition in the Eastern District of New York.
The federal review surfaced facts that had not been prominent at trial. Dr. Kanfer was still employed by the Connecticut medical examiner’s office in August 2013. The prosecution said he was on vacation for much of that month, but Dr. Carver testified he was unaware of any such vacation, and there was no indication prosecutors had asked Kanfer to reschedule or sought to delay the trial to secure his testimony.12GovInfo. Ganthier v. Superintendent, Green Haven Correctional Facility
On August 26, 2025, U.S. District Judge Nina R. Morrison granted the petition. She found that admitting Kanfer’s autopsy report through a surrogate witness violated the Confrontation Clause under Supreme Court precedent, and that the error was not harmless because the autopsy report was central to the prosecution’s case on cause of death. Judge Morrison vacated the conviction and ordered a new trial.12GovInfo. Ganthier v. Superintendent, Green Haven Correctional Facility
Where the Case Stands Now
The state appealed the habeas ruling to the U.S. Court of Appeals for the Second Circuit on September 26, 2025. As of the last available docket activity in October 2025, the appeal was pending, with a briefing schedule under discussion.17CourtListener. Ganthier v. Superintendent, Green Haven Correctional Facility Ganthier remains incarcerated at Green Haven Correctional Facility while the appeal proceeds.