MOM, KID, 14, SLAIN

Stabbed & beaten in their Bx. apt

A mother and her teenage son were fatally stabbed, strangled and bludgeoned with a gym weight in their Bronx apartment by a fiend who callously threw torn-up money on the woman’s body before fleeing, sources told The Post.

Marisol Ortiz, 51, of Belmont, and her youngest son, Alanche del Orbe, who was a day away from turning 15, were found dead at 3:38 p.m. Sunday in their East 185th Street apartment and police were searching into the late-night hours for the woman’s ex-con boyfriend, sources said.

The crime was incredibly vi- cious. While both had been bashed with a heavy weight, the mother was also stabbed in the head and the boy strangled, according to law-enforcement sources.

Ortiz’s 22-year-old daughter discovered the bloody bodies.

“I just heard the daughter screaming,” an upstairs neighbor Iris Rosa, 58, told The Post. “I didn’t hear no words. It was just ‘Ahhhhh!’ And then nothing.”

The daughter, whose name was not released, had rushed home after the mom’s colleagues called to say she hadn’t been to work Sunday.

Ortiz, a business owner, had not shown up in the morning to open her store, and her distraught daughter called police.

“She was on the sidewalk, on the phone,” Rosa said. “She was crying.”

When cops arrived, they found the mom dead on the floor in one room and the boy, who may have been attacked as he slept, dead on a bed in another.

A bloody knife was found near the teen. Cops believe the killer left an exercise weight by each body after using them to bludgeon their heads, according to a law-enforcement source.

A source also said cops found torn money on the mom’s body, but could give no more details.

Police did not immediately release the name of the boyfriend, who sources said has a prison re- cord for assault.

Cops could not say exactly when the murders happened, but a neighbor, Angel Cabrera, told NBC News that he heard screaming at 1 or 2 a.m., but had thought it was from a party.

Haydee Leonardo, del Orbe’s grieving cousin, told The Post outside the apartment Sunday night, “Tomorrow is his birthday.”

The youngster’s Facebook page shows him to have been a Yankees fan who enjoyed rap music and playing baseball with his father.

“It’s incredibly sad,” Leonardo said.

VICIOUS: Police remove evidence from the East 185th Street building Sunday evening after the bodies of Alanche del Orbe (inset) and his mom were found.