TWO SOUTH Philly families were torn apart on Feb. 11. This morning, they hope new light will be shed on what happened that night on Watkins Street.

Amber Hellesten, 15, faces a preliminary hearing today on murder and related offenses after she allegedly stabbed Azim Chaplin, 14, in the chest nearly three months ago on Watkins near 21st, in Point Breeze.

Chaplin, whose heart was pierced in the attack, died a few days later at Children's Hospital of Philadelphia, according to police.

What led to the stabbing is unclear: Stories buzzing around the neighborhood vary from a petty argument turned deadly to a premeditated attack weeks in the making.

To hear Nicole Hellesten tell it, her daughter acted out of desperation.

"Amber would never do anything like this unless she was scared to death," Hellesten said. "She panicked. She didn't know what to do."

Hellesten's information comes from one of Amber's friends, who allegedly was with her on the night of the attack.

She says that Amber and her friend were walking home that night when they were approached by a group of boys. Those boys taunted the girls, she says, later escalating the encounter by throwing bottles at them and hitting them with boards. Eventually, Amber was backed into a corner by the group, according to her mom.

Police say that what happened next is clear: Amber pulled out a black-handled pocket knife and stabbed Chaplin in the chest, according to the arrest report.

"She was justified in her actions," said David Desiderio, Amber's lawyer. "At the very least, she believed her life was in danger, and she reacted.

"It was a purely defensive maneuver. She never intended to kill anyone, but, unfortunately, this resulted in a tragic death."

According to the arrest report, a witness told investigators a different story: That Hellesten and a group of her friends were the aggressors, taunting Chaplin and his friends about their mothers.

Another witness positively identified Hellesten to police, and a search of her house later yielded the knife apparently used in the stabbing.

Meanwhile, Lynette Chaplin, Azim's mother, maintains that her son was killed over a neighborhood dispute, allegedly over a girl. She told the Daily News last night that her son had received threatening Facebook messages before his death.

"I just want to hear the truth," Chaplin said. "I want to hear exactly what they say is going on. I want to know what's going on with [Amber]."