A man convicted of stabbing a Winnipeg woman to death outside her St. Vital apartment building in June 2012 has had his appeal to the Supreme Court of Canada dismissed.

That means Treyvonne Willis, 24, will remain behind bars, where he was sent in April 2015 after being found guilty of first-degree murder and sentenced to life in prison without eligibility for parole for 25 years.

Kaila Tran, 26, was stabbed 30 times in the parking lot of her building near Bonita Avenue and Clayton Drive, along the bank of the Seine River, in broad daylight.

It was 7 a.m. and she was heading for work, according to information that came out during Willis's trial. The murder weapon was later recovered from the river.

Willis sought a new trial, claiming he was forced into the slaying by drug dealers, but a panel of judges with Manitoba's highest court denied his appeal in December 2016.​

Kaila Tran, 26, was stabbed 30 times in the parking lot of her building near Bonita Avenue and Clayton Drive, along the bank of the Seine River, in broad daylight. (Teleco.ca)

Willis then sought leave to appeal to the Supreme Court, but on Thursday his application was dismissed.

"The applicant faced death threats over a drug debt. The dealers threatening him also wanted Ms. Tran killed for an unrelated reason," states the Supreme Court ruling, which summarizes the appeal application.

"In order to avoid the threat, the applicant chose to commit the murder of Ms. Tran."

The Supreme Court ruling says Willis was seeking to put forward a "defence of duress" based on a claim that he was in kill-or-be-killed situation.

After his arrest, Willis had told police the murder was necessary because "[i]t was like my life or her life," the ruling notes.

The original trial judge dismissed that defence, as did the panel of judges with the appeal court.

On Thursday, the Supreme Court did as well.