Jennifer Gould

With this Crime Alert, I'm Jennifer Gould.

I'm Jennifer Gould.

A savage apartment complex brawl involving a mob of 30 screaming people took a gruesome fatal turn when a 10-year-old boy allegedly plunged a knife into the chest of a 13-year-old girl.

The blood-soaked tragedy unfolded around 8 p.m.

at a home in the 8,000 block of Grow Lane in northwest Houston, Texas.

Riley Dermis, a 13-year-old student at Dean Middle School, was left suffering from a catastrophic stab wound as the massive group of juveniles and adults scattered into the night.

She was rushed to a nearby hospital but died of her injuries.

The victim's mom, Ashley Diermas, spoke to the media at a memorial for her little girl.

The 10-year-old suspect, a resident of the Kempwood Apartments, turned himself into the Houston PD and offered a chilling justification for the killing, self-defense.

HPD Lieutenant Larry Croson revealed the boy's claim that Riley was part of a marauding swarming of 20 to 30 people who stormed the apartment and began a violent assault on all the residents inside.

Investigators believe the deadly confrontation was the explosive culmination of a school day dispute that boiled over into the evening.

But Ashley Dearmas is blasting the self-defense narrative as a cruel lie, saying, quote, there was no self-defense.

My daughter was attacked.

She didn't deserve this, end quote.

While the boy was initially released to his parents, the Harris County DA's office is now weighing formal charges.

Under Texas law, 10 is the minimum age for criminal responsibility, meaning the boy could face a homicide rap for the slaying.

As of now, no other arrests have been made.

Forensic teams are reviewing grainy cell phone footage of the 30-person melee

to ID the dozens of participants who took part and witnessed the girls' final moments.

More crime and justice news after this.