Left: Boris Lainez-Rosales (Atlantic County Prosecutor”s Office). Right: Leslianette Quintana-Betancourt (Tribute Archive).
A New Jersey man has admitted to beating his pregnant girlfriend to death “with a baseball bat” at their home and then staging a scene to make it look like she fell down a staircase, according to prosecutors.
Boris Lainez-Rosales, 28, of Pleasantville, pleaded guilty last week to one count of first-degree murder in connection with the death of his live-in girlfriend, Leslianette Quintana-Betancourt, 25, also of Pleasantville.
“In pleading guilty, the defendant admitted that on December 2, 2024, he assaulted the victim, who was his domestic partner, and pregnant at the time, with a baseball bat at his home in Pleasantville, causing her death,” the Atlantic County Prosecutor’s Office says in a press release.
A probable cause affidavit obtained by the Courier-Post describes how a witness who was in the couple’s home heard Lainez-Rosales and Quintana-Betancourt arguing from 9:30 p.m. to 11 p.m. that night. The person went downstairs to see what was happening and was “escorted back upstairs by Lainez-Rosales, who said everything was fine,” according to the affidavit.
“A short time after that, Lainez-Rosales came up the stairs to the main living quarters and used the witness’s phone to call 911,” the affidavit says.
When cops and first responders arrived, they found Quintana-Betancourt’s body at the bottom of a 12-step staircase. She had multiple blunt-force injuries to her face, arms and abdomen, as well as a ruptured placenta. Her unborn child did not survive.
“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.
