VANCOUVER -- Two Vancouver police officers who decided not to warn a pregnant woman about a tip that someone was plotting to kill her in the days before she was murdered have lost a court attempt to block an investigation into their conduct.

Det. Const. Craig Bentley and Staff Sgt. John Grywinski were working on the region's integrated gang task force in 2005 when Bentley received a tip that someone was attempting to hire a hitman to kill 21-year-old Tasha Rosette.

The B.C. Supreme Court heard Bentley told Grywinski, his supervisor, but the pair decided to further investigate the tip rather than warn Rosette.

Five days later, Rosette was found stabbed to death outside the door of her apartment in Surrey, southeast of Vancouver. She was stabbed 40 times and her throat was slashed.

Her boyfriend, Amjad Khan, and his alleged accomplice, Naim Mohammed Saghir, were later convicted of murder and conspiracy to commit murder, though the province's Appeal Court overturned those convictions last year and ordered a new trial.

Two complaints linked to the case were filed with the Vancouver Police Department: Simone Rosette, the woman's mother, alleged the officers neglected their duty by not warning her daughter, while the Crown raised concerns about Bentley's testimony at the preliminary inquiry for Khan and Saghir.

The department dismissed those complaints after an external review by the RCMP.

But the province's police complaints commissioner ordered an external force to investigate again because, in the commissioner's view, the Vancouver Police Department didn't consider all of the information available when dismissing the complaint.

Bentley and Grywinski asked the court to stop that renewed investigation, arguing the Vancouver Police Department's initial decision to dismiss the complaints was final and that the police complaints commissioner missed a deadline to order a new investigation.

They challenged the commissioner's order in 2009 that the case be investigated again, and another order in 2010 that an outside force take it over from the Vancouver Police Department.

However, the court rejected their petition in a ruling issued this week.

"In my view, the petitioners' argument is overly technical," Judge Laura Gerow wrote in a decision posted to the court's website.

"This is not a case where the petitioners are caught by surprise or can point to any prejudice. ... The fact that the petitioners did not commence a petition until after the 2010 order for an external investigation was made, and allowed the investigation to proceed for 19 months before commencing a petition, is indicative of the fact that they were well aware of the reason for the 2009 order and were content with it."

A spokesman for police complaints commissioner's office declined to comment on the court decision, but noted the Abbotsford Police Department has been assigned to look at the case.

The commissioner doesn't directly investigate complaints. Instead, the commissioner oversees investigations conducted by either the police force involved in the complaint or an external force.

Details of the tip emerged at Khan's and Saghir's murder trial in 2008.

The Crown alleged at the earlier trial that Khan wanted to kill Rosette because she was pregnant with his child and refused to have an abortion.

Khan testified in his own defence and denied having anything to do with Rosette's murder or ever raising concerns about the pregnancy.

Khan and Saghir appealed. Last year, the B.C. Court of Appeal overturned their convictions and ordered a new trial.

The court concluded the Crown violated Khan's right to a fair trial during cross-examination and that the judge gave incorrect instructions to the jury.