The mother of a man who cops believed tortured and killed his 21-year-old girlfriend — leaving her to die on a Bronx staircase — has been arrested after investigators determined she helped clean up the gruesome crime scene, officials said.

Naida Jorge, 54, was charged Thursday evening with murder, manslaughter, hindering prosecution, concealment of a human corpse and tampering with physical evidence over the tragic slaying of Princesa Encarnacion-Soto.

“She did attempt to clean up the crime scene,” NYPD Chief of Detectives Joseph Kenny told reporters.

Cops believe Naida Jorge, 54, scrubbed the scene after 21-year-old Princesa Encarnacion-Soto was brutally murdered, authorities said. Brigitte Stelzer

Police were still looking for Robert Strother, 27, the dead woman’s boyfriend, in connection to the murder, cops said.

The victim, who was barely breathing when officers found her bruised body Tuesday, had been tied up and subjected to sadistic torture inside a Fordham Heights apartment before being dumped on the stairs.

“There was no blood on her while she laid on the staircase, and she was in fresh clothing that had no blood on her. So [there is a] possibility that someone cleaned the body, put fresh clothes on her and threw it on her by the staircase,” Kenny said Thursday.

Cops responding to a 911 call, who discovered Encarnacion-Soto, followed a trail of blood that led into the Grand Concourse apartment where Strother is believed to have allegedly tormented the young woman.

“The wounds themselves were inflicted for pain, not to kill,” Kenny said.

Encarnacion-Soto was tied up, stabbed from head to toe, and possibly beaten with a hammer before she was dumped in the stairwell, police and law enforcement sources said.

Murder victim Princesa Encarnacion-Soto, 21, was subjected to repeated torture inside the Grand Concourse apartment, cops said. Facebook

“We believe that she was tied down to the bed based on the blood that was on the bed,” Kenny told reporters. “There were slice marks on her thighs, slice marks on her upper arms, and shoulders. The ones on her legs were fresh. The ones on her upper torso seemed like they were in the process of healing.” 

Encarnacion-Soto, who later succumbed to her injuries, had returned to the Bronx July 11 after leaving Strother and traveling to Rhode Island to stay with her mother, the distraught woman, Jocibelle Soto, 39, told El Diario. 

“They were together for almost three years. She met him on Instagram,” the victim’s mother told the newspaper. “My daughter left him and came back home.”

Princesa Encarnacion-Soto was left to die on this staircase of her Bronx apartment building. Brigitte Stelzer

Encarnacion-Soto was living with Strother and his mother when she returned, police said.

A photo obtained by The Post from inside the horror home showed layers of grime and debris.

Strother was spotted on security cameras leaving the Bronx building and remained on the loose Friday, sources said.

In a cruel twist, Kenny said police were called in May by Strother, who claimed that Encarnacion-Soto had been raped by a group of men on the roof of the building.

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Cops determined the report was bogus — and now believe the call was an attempt to hide the abuse that Encarnacion-Soto had been suffering in the apartment.

“The mom and son fabricated the rape story because our victim here was injured to the point she needed medical attention,” Kenny said.

The mother and son’s downstairs neighbor, who only identified herself as Maria F., told The Post Friday that the pair was “violent” and “were always going at it over different things,” with “different banging going on.”

Cops are still looking for Encarnacion-Soto’s boyfriend, Robert Strother, 27, who they believe subjected her to repeated torture, police said. Kyle Mazza/NurPhoto/Shutterstock

“The mother is trouble. I know she’s crazy but her son is the violent one,” the woman said. “Since he was a little kid he was always a trouble maker. Verbally and physically, to everyone — men and women.”

Judge Harold Bahr ordered Jorge held without bail during her Friday arraignment in Bronx Criminal Court. 

“She’s alleged to have assisted her son in trying to cover up a murder scene,” indicating an attempt to avoid prosecution, Bahr noted.

A photo obtained by The Post from inside the apartment shows layers of grime and debris inside the home where Encarnacion-Soto was tortured and killed. Kyle Mazza/NurPhoto/Shutterstock

Her defense lawyer, Jason Gazewood, argued Jorge “has been a law-abiding citizen for the entirety of her life” as he sought for her to be released on supervision with electronic monitoring.

Jorge previously worked for the Parks Department and the MTA, according to the attorney, but had to quit because of health issues. 

Gazewood also argued that court filings don’t provide many details about Jorge’s alleged actions in the case, and do not connect her to the brutal injuries inflicted on the victim.

“It looks like this is a case where this is not someone who is culpable for a murder charge,” he said. “It looks more like activities post to whatever happened to this person.”

Jorge is due back in court next week.