She took a DNA test for fun. Police used it to charge her grandmother with murder in a cold case

Jenna Gerwatowski, left, says the case was always a big mystery in her town. She had no idea the grandmother she'd never met, Nancy Gerwatoswki, right, could be behind it. (Jenna Rose Gerwatowski / Mackinac County Sheriff's Office via CNN Newsource)

Content warning: This story includes mention of the death of a child. Reader discretion is advised.

It was the middle of Jenna Gerwatowski’s workday at the local flower shop in Newberry, Mich., when she got a call from an unknown number.

The now 23-year-old doesn’t usually answer unknown calls, but says she decided to pick this one up in May 2022.

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To her surprise, it was a detective from the Michigan state police.

“He was like, ‘Have you heard of the Baby Garnet case?’” Jenna told CNN.

Jenna had heard of it. In 1997, a deceased infant was found in a campground pit toilet at the Garnet Lake Campground – right where Jenna grew up. Investigators couldn’t find any leads on the identity of the baby or anyone who witnessed a person abandoning an infant, according to a news release from the Michigan attorney general’s office. The case went cold, and the “Baby Garnet” case became a known murder mystery in Jenna’s small town for decades.

“Your DNA was a match,” Jenna says the detective on the phone told her. She was related to the dead infant from 1997.

Jenna was in shock. The detective sounded sure, Jenna said, but she wondered how he had even obtained her DNA.

About six months earlier, her friend had gotten a FamilyTreeDNA test for Christmas and Jenna decided to order her own. DNA from other Baby Garnet relatives led detectives to Jenna’s FamilyTreeDNA kit, according to court documents.

The detective said a woman from Identifinders International, a genetic genealogy investigation firm, would call her about her DNA to help with identifying closer relatives, according to Jenna.

According to court documents, detectives reopened the cold case in 2017 and then worked with a forensics company to extract DNA from Baby Garnet’s partial femur, before sending the results to Identifinders International.

Jenna explained the situation to her mother when she got home from work.

“It was just crazy,” Jenna said. “We were both sitting there like, I don’t even know who (the mother or father) could’ve been. We were both so confused and we’re like, it’s got to be somebody that we don’t know, you know, like a distant cousin or something.”

Jenna said her mother, Kara Gerwatowski, started to wonder whether the detective call was a scam.

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Jenna’s grandfather had just been scammed by someone claiming to be a detective, so Kara told Jenna to be cautious about giving out personal information or passwords.

Misty Gillis, then a senior forensic genealogist and cold case liaison from Identifinders International, called Jenna that night, according to Jenna and court documents filed later in the case.

Jenna claims Gillis requested her FamilyTreeDNA password to be able to upload her DNA into a separate database. Jenna was concerned it was a scammer and refused to cooperate, according to court documents.

“I hung up the phone on her, not even thinking twice about it. And we went about our day. I was like, how weird. What a weird thing to scam people about,” Jenna said. “I wholeheartedly did not think that it was real.”

One week later, Jenna was working at the flower shop when she got a distressed call from her mother.

“She was like, ‘I really need you to come home. … It’s an emergency. Like, just please come as soon as you can,’” Jenna said.

Jenna rushed home thinking someone died. Her cousin was sitting with her mom at their round wooden kitchen table. Police had contacted her cousin, who works as a victim’s advocate in the county prosecutor’s office, to explain the Baby Garnet situation to Jenna. It turned out it wasn’t a scam.

“My mom had tears in her eyes,” she said. Jenna’s cousin had “just pure shock on her face. … You could hear a pin drop in there.”

Even though Jenna knew she had nothing to do with the Baby Garnet case, she was terrified police would think she was trying to hide something because of her refusal to speak with Gillis. She immediately called her.

An analysis of Jenna’s DNA kit showed she was the half-niece to Baby Garnet, according to court records.

On June 1, 2022, detectives spoke with her mother, Kara, who agreed to provide her DNA. Kara was the half-sister of Baby Garnet, according to court records.

“I feel like that is when, like, all of the puzzle pieces kind of started falling together for her,” Jenna said. “And she told detectives that, if it’s going to be anybody, it would be (her) mother.”

Kara, now 42, had not spoken with her mother, Nancy Gerwatowski, since she was 18 because they had a bad relationship, and Jenna had never met her grandmother. Regardless, both were shocked Nancy, who was living in Wyoming when police questioned her, would be the one behind their town mystery.

“I had grown up knowing about the case my whole life and then come to find out it was my grandma that did it?” Jenna said.

The Michigan attorney general’s office alleges Nancy “delivered the newborn alone at her Newberry home, during which Baby Garnet died due to asphyxiation, and that this death could have been prevented by medical intervention (Nancy) Gerwatowski did not seek.”

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However, in a court filing, Nancy’s defence argues she unexpectedly gave birth while in the bathtub and the fetus “became trapped inside her birth canal.” She “attempted to pull the fetus out of her own body,” the filing says, but couldn’t deliver the fetus and lost consciousness “at some point in the delivery.” When she was finally able to deliver the fetus, it was dead, the filing says.

Her defence argues that Nancy, like the average person in the county in 1997, did not have access to a telephone or cell line, so she couldn’t call 911. While she concedes in her legal filings she placed the stillborn fetus in a bag and left the remains at the campground, her defence attorneys argue she had been in shock after having had no pain medication during the traumatic birth.

Nancy is charged with one count each of open murder, involuntary manslaughter, and concealing the death of an individual. Open murder carries a potential life sentence. Her defence is hoping to get the case against Gerwatowski dropped in its entirety Thursday, arguing the “state cannot prove the fetus was born alive,” according to the court records filed by Nancy Gerwatowski’s defence lawyer.

“It was a very hard time … very traumatizing and very nerve-wracking,” said Jenna. “I’ve never met this woman, so it was hard for me to even grasp that concept, but even harder for my mom because that was her mother.”