A young woman convicted of murder for using taunts and sexual blackmail to pressure her boyfriend into killing a 14-year-old girl is innocent, her lawyer said Wednesday after appealing her case.

Melissa Todorovic told police, shortly after her boyfriend stabbed Stefanie Rengel six times and left her to die in a snowbank on New Year's Day 2008, that the murder was more her idea than her boyfriend's.

During the police interviews the 15-year-old girl admitted she knew David Bagshaw was heading to Rengel's house that night to kill her, that she called him 15 minutes after the murder asking, "Is she dead?", and that she asked Bagshaw to come over to her house so he could demonstrate how he had killed Rengel.

But mistakes that police made in taking those statements mean they never should have been allowed as evidence at her trial, lawyer Brian Snell told the Court of Appeal for Ontario.

"The admissibility of those statements went a long way to convicting her and it was a miscarriage of justice that that happened," Snell said after the hearing.


Stephanie Rengel had once dated her killer David Bagshaw. (Courtesy Toronto Police Service)

Both the families of Rengel and Todorovic were at the Appeal Court to hear the arguments.

Todorovic never met Rengel, but the younger girl became the target of intense teenage jealousy since she had briefly dated Bagshaw two years earlier and Todorovic believed Rengel was spreading rumours about her.

Todorovic also told police at the time that she didn't think Bagshaw would take her seriously when she told him to kill Rengel, saying she was only joking. That became the defence theory of the case.

"She should not have been convicted, in my view," Snell said outside court. "She was innocent because she's only guilty if she intended Bagshaw to carry out this terrible crime."

Police brought Todorovic in for an interview in the aftermath of Rengel's murder and didn't properly explain her rights, Snell argued, including telling her that she didn't have to give them a statement and that if she did, she needed to have the duty counsel lawyer there who she had briefly consulted on the phone. She waived those rights, but Snell argued that wasn't an informed decision.

Snell argued that Todorovic was already detained when she told police about her involvement and police already had grounds to believe she had committed a crime, which would trigger Todorovic's rights under the Youth Criminal Justice Act.

But the Crown argued that police only had a thin suspicion when they brought her in that she was involved, and that they treated her like all the other witnesses. Police only detained her after she made the incriminating statements, the Crown said.

The Crown argued that any mistakes police made in explaining Todorovic's rights to her under the YCJA were technical in nature and an honest oversight. But, even if her statements had been thrown out, the Crown's case was "overwhelming," Crown Attorney Jamie Klukach said.

At trial the Crown presented reams of messages between the young couple in which Todorovic threatens to break up with Bagshaw or withhold sex until he kills Rengel.

But, Snell said, Todorovic's frequent punctuation of her threats with the phrase "lol" show she was joking and didn't mean for Bagshaw to actually commit murder.

If the Appeal Court dismisses Todorovic's attempt at a new trial, her lawyer asked them to change her adult sentence to a youth one.

Todorovic was sentenced as an adult to life in prison with no chance of parole for seven years - the maximum adult sentence for someone her age.

A youth sentence would see her serve a total of 10 years — six behind bars and four of community supervision.

The Appeal Court judges reserved their decision, but promised to issue a ruling "as quickly as we can."

Bagshaw, who was days away from his 18th birthday when he stabbed Rengel, pleaded guilty to first-degree murder and is serving an adult sentence.