Left: Boris Lainez-Rosales (Atlantic County Prosecutor”s Office). Right: Leslianette Quintana-Betancourt (Tribute Archive).
In a chilling and tragic case, a man from New Jersey has confessed to the brutal murder of his pregnant girlfriend, reportedly attacking her with a baseball bat and then attempting to disguise the incident as a fall down the stairs, as detailed by local prosecutors.
Boris Lainez-Rosales, aged 28 and residing in Pleasantville, recently admitted his guilt in court, pleading to a first-degree murder charge related to the death of his 25-year-old partner, Leslianette Quintana-Betancourt, who also lived in Pleasantville.
The Atlantic County Prosecutor’s Office issued a public statement, pointing out that in his guilty plea, Lainez-Rosales acknowledged the violent assault on December 2, 2024. He admitted to using a baseball bat against Quintana-Betancourt, who was pregnant at the time, resulting in her death.
Details from a probable cause affidavit, as reported by the Courier-Post, revealed that a witness within the household overheard a heated argument between Lainez-Rosales and Quintana-Betancourt between 9:30 p.m. and 11 p.m. that evening. When the witness attempted to investigate, Lainez-Rosales reportedly reassured them that everything was under control and led them back upstairs.
Shortly afterward, Lainez-Rosales ascended to the main living area once more, this time using the witness’s phone to dial 911, as the affidavit indicates.
Upon arrival, law enforcement and emergency responders discovered Quintana-Betancourt at the foot of a 12-step staircase, her body bearing multiple blunt-force injuries to the face, arms, and abdomen, as well as a ruptured placenta. Tragically, the unborn child did not survive the incident.
“There were no blood stains in and around the stairwell,” the affidavit says, according to the Courier-Post. Police said Quintana-Betancourt’s body “smelled of bleach.”
While speaking to cops, Lainez-Rosales had cuts on his hands. He claimed Quintana-Betancourt fell down the stairs and that he called police afterward.
Investigators searched the home and found bloodstains throughout the couple’s basement living area and on the walls. Investigators detected the smell of bleach throughout the apartment along with “evidence of attempts to clean up biological evidence,” per the affidavit.
Police found a baseball bat in the backyard that had bloodstains on it and recovered a trash bag in Lainez-Rosales’ car “with possible hair attached,” according to the affidavit. He was arrested and later indicted for Quintana-Betancourt’s murder in February 2025.
“You were so happy about becoming a mom,” a friend wrote on Quintana-Betancourt’s tribute wall for her online obituary. “You were such a sweet and kind young lady that had a laugh and smile that would brighten up a room,” the pal said.
Lainez-Rosales’ plea calls for a recommended sentence of 30 years without the possibility of parole, according to the prosecutor’s office. He is scheduled to be sentenced on July 31.
