The young man who viciously stabbed teenager Stephanie Rengel to death will learn his fate on Sept. 28.

Justice Ian Nordheimer has reserved decision until that date in the case of D.B., who pleaded guilty back in April to first-degree murder.

If he sentences D.B. as an adult, the now-19-year-old will receive a penalty of life in prison with no possibility of parole for at least seven years.

A youth sentence (D.B. was four days shy of his 18th birthday at the time of the murder) would see him received a custodial term of six years (adjusted for time served) plus another four years in open custody.

On July 28, Nordheimer sentenced Melissa Todorovic, D.B.'s girlfriend of the time, as an adult. That allowed the media to name the 17-year-old.

Todorovic had relentlessly pressured D.B. to kill Rengel, someone she had never met but for whom she harboured a pathological jealousy. They exchanged thousands of text messages and cellphone calls over a period of months.

He finally acted on the evening of Jan. 1, 2008, luring Rengel outside with a phone call and then stabbing her six times. A passerby found Rengel dying, moaning that it hurt so bad.

Court observers have said D.B. has shown more remorse than Todorovic did.

The Crown is arguing for an adult sentence, while the defence has presented expert testimony that adult incarceration would leave D.B. as more antisocial than if he received help in a youth facility.