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Nearly 30 years after a 10-year-old girl went missing, a Quebec inmate is charged with her murder. A daughter faces her mother’s alleged killer in court — her father. Two DNA tests, conducted four decades following a seamstress’s brutal death, result in an arrest and conviction.

These are some of the cold cases in Canada that saw breakthroughs in 2023.

But many crimes and disappearances remain unsolved. More than 2,500 adults and children in Canada are missing, based on the Canadian national RCMP database, said Jan Guppy, who created the Facebook group Unidentified Human Remains Canada.

Guppy, from the Montreal area, said 378 people who are missing are unidentified. Guppy said the figures are “way too low and completely inaccurate” because provinces are not required to provide numbers.

Here are some of the Canadian cold cases that saw breakthroughs in 2023 as well as some of those that remain unsolved in 2024:

BREAKTHROUGH IN KILLING OF QUEBEC GIRL

“Innovative methods” in forensic biology are being credited with helping investigators arrest a suspect in the killing of a 10-year-old Quebec girl nearly 30 years ago.

The suspect was identified and arrested following “the meticulous, long-term work” of investigators and forensic staff, according to the Quebec police force’s press release.

Marie-Chantale Desjardins, 10, was last seen on her bike leaving her friend’s home at about 9:30 p.m. in Sainte-Thérèse, Que., on July 16, 1994. Witnesses reported spotting her that day at a local billiard bar that police said she had frequented.

Days later, her body was found in a wooded area behind a shopping centre in the nearby municipality of Rosemère. Pathologists suspect she was strangled.

Twenty-nine years after she disappeared, there was a breakthrough in the cold case on Dec. 12, 2023. Réal Courtemanche, 61, was arrested at a medium-security prison about 190 kilometres northwest of Montreal, and charged with first-degree murder, according to police.

N.L. HUSBAND CHARGED WITH WIFE'S MURDER

Jennifer Hillier-Penney was separating from her husband when she disappeared in 2016 — a case that shocked the small town of St. Anthony, N.L.

The last time Hillier-Penney was seen was Nov. 30, 2016, when her sister dropped her off at her estranged husband Dean Penney’s house so she could spend time with their daughter.

Seven years later on Dec. 15, 2023, RCMP charged her estranged husband, Penney, with first-degree murder in connection with her disappearance. Police called the high-profile case one of the longest and most complex investigations. Police are still searching for Hillier-Penney's remains.

DNA SAMPLES LEAD TO CONVICTION

Soon after Montreal native Sonia Herok-Stone moved to the tiny California town of Carmel-by-the-Sea, she was found partially naked, bloodied and strangled to death with her pantyhose in 1981, according to Det. Lins Dorman.

Police questioned Michael Glazebrook, a 25-year-old married tradesman who lived across the street. He denied killing the 30-year-old seamstress, but said he was having an affair with her and was at her house the day of the murder.

In 1982, he was charged with first-degree murder in her death. However, a judge ruled Glazebrook’s statement was inadmissible because police violated his rights by picking him up on traffic warrants.

Although Glazebrook’s trial ended in a hung jury in 1983, the Monterey County District Attorney’s office re-opened the case in 2020. A search warrant allowed police to get a sample of his DNA in 2021. The blood under the victim’s fingernail was a match and Glazebrook was charged with first-degree murder for the second time. Months later, police also collected a DNA sample from Herok-Stone’s breast swabs that matched with Glazebrook’s DNA.

More than 40 years on, the two DNA samples led to his conviction in February 2023. Glazebrook was found guilty of first-degree murder and sentenced to life in prison with no chance of parole in June. The school bus driver, 67, has never confessed.

‘NATION RIVER LADY’ IDENTIFIED

For nearly 50 years, the identity of the “Nation River Lady” remained a mystery. A farmer discovered the woman’s remains floating in the Nation River in eastern Ontario on May 3, 1975.

Green cloth covered her body. Her hands and feet were bound with neckties.

Thanks to genealogical DNA testing meant to find genetic matches, the U.S. non-profit DNA Doe Project (DDP) announced in July 5, 2023 that it had identified the woman as Jewell “Lalla” Parchman Langford, 48, a businesswoman from Jackson, Tenn. That same day, the Ontario Provincial Police revealed that they had charged Rodney Nichols, 81, of Hollywood, Fla., with murder in September 2022. They said they delayed the public announcement to avoid jeopardizing the investigation and court process. Police said the victim and accused knew each other.

The OPP worked with experts to exhume the body and create a new DNA profile in late 2019 that eventually led to confirmation in 2020 that Langford was the “Nation River Lady.” Her remains were finally buried after they were repatriated to the U.S. in March 2022.

The defence is seeking a fitness assessment order so that experts can assess whether Nichols is fit to stand trial since he has dementia, his Toronto-based lawyer Laura Metcalfe told CTVNews.ca in an email.

ARREST IN 50-YEAR-OLD CASE

New DNA technology helped OPP lay charges against a 78-year-old man in the 1973 death of a woman from the northern First Nation of Attawapiskat. Helen Carpenter, 21, was found dead on Oct. 23, 1973.

An investigation turned up no charges at that time, police said.

Fifty years after her death, Remi Gregory Iahtail of Attawapiskat, who was 28 when Carpenter disappeared, was charged with manslaughter and rape in October.

The case will be heard at Attawapiskat Ontario Court of Justice on Jan. 17,, 2024.

CREE WOMAN'S DEATH RAISES SUSPICIONS

More than three years after Chelsea Poorman went missing from downtown Vancouver in 2020, her family and Indigenous advocates are still searching for answers.

Poorman, 24, was last seen near Granville and Drake streets around midnight on Sept. 7, 2020.

A member of the Kawacatoose First Nation in Saskatchewan, she had just moved to Vancouver at that time.

Nearly two years after she disappeared, Poorman's remains were discovered in an abandoned mansion in the upscale Shaughnessy neighbourhood on April 22, 2022.

Her mother Sheila said her daughter’s remains were found in a blanket on the balcony, missing some fingers and her cranium.

Vancouver officials have not revealed how she died and police said there isn't enough evidence to call her death suspicious.

But family members and Indigenous advocates say the circumstances of her death are suspicious.

PREGNANT WOMAN’S DEATH A MYSTERY

Sonya Cywink of London, Ont., was 24 weeks pregnant when her body was discovered in 1994. Police said she was last seen alive at about 2 a.m. on Aug. 26, 1994. Four days later, her body was found at the Southwold Earthworks National Historic Site of Canada, southwest of London.

She was originally from the Whitefish River First Nation territory on Manitoulin Island.

“We’re still out there looking for leads, looking for people to come forward,” the victim’s sister Meggie Cywink told CTV News in October 2023.

LETTER WRITER ADMITS TO KILLING

In an anonymous letter to Vancouver police, a writer admitted to killing an Indigenous sex trade worker, whom the person didn’t name, who had disappeared on Nov. 30, 2002 and apologized to her family.

Police received it on Dec. 31, 2002, a month after Danielle Marissa Lynn Larue went missing. Though the body of Larue was never found and she wasn’t explicitly named, police believe she was murdered.

Police believe the letter writer knows where her body is buried and hope the person will contact them again.

Larue was in foster care, ran away when she was just 13 in Prince George, B.C., and turned to drugs to cope with her trauma of being abused as a child, they added. Larue, who was 24 when she disappeared, became a sex trade worker in Vancouver to support her drug addiction, police said.

With files from CTVNews.ca, CTV National News, W5, CTV News Regina, CTVNewsLondon.ca, CTV News London, CTVNorthernOntario.ca, CTVNewsVancouver.ca, CTVNewsMontreal.ca and The Canadian Press