Investigators said the scene at a Pleasantville home did not match the story first given to police.
PLEASANTVILLE, N.J. — A 911 call about a woman at the bottom of a staircase became a murder case after police found blood in a basement, bleach odors and a bat outside, authorities said.
The woman, Leslianette Quintana-Betancourt, 25, was pregnant and living with Boris Lainez-Rosales, 28, when she died in December 2024. Lainez-Rosales has since pleaded guilty to first-degree murder. Prosecutors said he admitted that he killed Quintana-Betancourt with a baseball bat and tried to make the death look like a fall.
The first account came through an emergency call around 2 a.m. Dec. 3, 2024. Lainez-Rosales told authorities that Quintana-Betancourt had fallen down about 12 steps and was unresponsive. Police and medical responders went to the home and found her slumped at the bottom of the stairs. At that moment, the call framed the scene as a possible household accident. Investigators later said the physical evidence inside the home did not support that version. Their work started at the stairwell but quickly expanded to the basement living area, the backyard and Lainez-Rosales’ vehicle.
Police said there were no blood stains in and around the stairwell, a detail that stood out because Quintana-Betancourt had severe injuries. Her body smelled of bleach, investigators said. Lainez-Rosales had cuts on his hands while speaking with officers. He maintained that she had fallen and that he had called police afterward. The absence of blood near the stairs became one of the facts that undercut the account he gave first responders. The case also involved injuries that prosecutors later said were caused by an assault with a bat, not by a fall inside the home.
Investigators found a different scene in the couple’s basement living area. Court records described bloodstains throughout that space and on the walls. Officers also detected the smell of bleach throughout the apartment and reported evidence that someone had tried to clean biological material. Those findings gave investigators a new path through the home. The basement, not the stairwell, became the place where police focused on what happened before the 911 call. The prosecution’s later account said Quintana-Betancourt had been dragged from a blood-soaked basement and left near the stairs.
The affidavit also placed a witness inside the home before police were called. The witness heard Lainez-Rosales and Quintana-Betancourt arguing from about 9:30 p.m. to 11 p.m. on Dec. 2, according to the document. The witness went downstairs, but Lainez-Rosales escorted the person back upstairs and said everything was fine. A short time later, he came to the main living quarters and used the witness’s phone to call 911. That sequence gave investigators a timeline beginning with the argument, continuing with the witness being moved away, and ending with the emergency call.
The injuries gave the case its next turn. Police said Quintana-Betancourt had blunt-force injuries to her face, arms and abdomen. She also had a ruptured placenta. Her unborn child did not survive. Prosecutors said the injuries were consistent with the assault Lainez-Rosales later admitted in court. The killing happened Dec. 2, 2024, according to the guilty plea. The emergency call came after midnight. By the time officers arrived, police said, the home showed signs that the original scene had been changed and cleaned.
Outside the home, investigators found a baseball bat in the backyard with bloodstains on it. In Lainez-Rosales’ car, they recovered a trash bag with possible hair attached. Those items became part of the evidence that moved the case beyond a disputed statement. The state did not have to test the fall account at trial because Lainez-Rosales pleaded guilty. In doing so, he admitted that he assaulted Quintana-Betancourt, who was his domestic partner and pregnant, with a baseball bat at the Pleasantville home, causing her death.
Lainez-Rosales was indicted in February 2025. Local reports said the initial charges included murder, tampering with evidence and possession of a weapon for an unlawful purpose. The guilty plea came May 19, 2026, in Atlantic County. The plea calls for 30 years in New Jersey State Prison without the possibility of parole. Prosecutors said the investigation was a joint effort by Pleasantville police and the Atlantic County Prosecutor’s Office Major Crimes Unit. Executive Assistant Prosecutor Rick McKelvey is handling the case for the state.
The case also left a public record of Quintana-Betancourt beyond the evidence. An online memorial described her as a beloved sister, daughter, aunt and friend. One friend wrote that she had been excited about becoming a mother. The memorial words contrasted with the court record, which described a home where a fatal assault was followed by an attempt to make the death appear accidental. Prosecutors have not publicly described a motive. The record also does not say what the argument inside the home was about.
On July 31, 2026, Lainez-Rosales is scheduled for sentencing before Superior Court Judge Joseph A. Levin. The recommended sentence is 30 years without parole, and the final judgment remains with the court.
Author note: Last updated June 21, 2026.