'That’s the Baby at My House:' Inside the Alleged Plot to Kidnap Heidi Broussard and Her Baby

Authorities say it’s unclear when Magen Fieramusca came up with the alleged plot to kidnap her best friend, as well as her infant, in order to pretend the baby was her own. But newly released court documents reveal the lengths they believe Fieramusca went to carry it out.

Fieramusca and Heidi Broussard, both 33, had been best friends for years since meeting at a Bible Institute when they were young.

As adults, they remained close, announcing pregnancies around the same time in early 2019 — Fieramusca with her first child, Broussard with her second, according to the arrest affidavit obtained by PEOPLE.

But all of that would change when Broussard and her two-week old daughter, Margo Carey, disappeared on Dec. 12, and the mother-of-two would be found dead, stuffed in a duffle bag in the back of Fieramusca’s car.

On Nov. 26, the day of Margo’s birth, Fieramusca was given a key to the apartment Broussard shared with her fiancé, Shane Carey, and their 6-year-old son.

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According to the affidavit, Fieramusca stayed the night at the couple’s home after being in the delivery room with Broussard and her family, promising to leave the key on the counter. But it would never be found, Carey later told investigators.

In early December, Carey said, Fieramusca told the couple she had given birth. However, she never sent Broussard or Carey pictures of the newborn girl.

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The next week, on Dec. 12, Broussard was spotted on a neighbor’s CCTV camera getting into a car with Fieramsuca while holding Margo, according to the affidavit. She would never been seen or heard from again.

During the search for Broussard, Fieramsuca allegedly kept up appearances by FaceTiming friends with a baby later revealed to be Margo.

She also searched the internet 162 times for “Heidi Broussard,” as well as searching for “bodies found in Austin Texas” and “reasons for AMBER Alert,” the affidavit claims.

Magen Rose Fieramusca | Courtesy of Humble Police
Magen Rose Fieramusca | Courtesy of Humble Police

Authorities began to conduct surveillance on Fieramusca and spoke with the owner of her home in Houston. When they showed him a picture of Broussard and Margo, the owner told them, “That’s the baby at my house,” according to the affidavit.

The home-owner told authorities he and Fieramusca had dated but had broken up in March and still lived together, though it is unclear if the owner is the same person referenced in the affidavit as Fieramusca’s boyfriend. The owner said Fieramusca told him she was pregnant but said he never saw Fieramusca’s bare stomach. He said he believed he was the father of her supposed child.

Then, the owner said, on Dec. 13, Fieramusca came home and said “don’t be mad, don’t be mad,” revealing there was a baby on her bed, according to the affidavit. She told him she had gone into labor and given birth at a birthing center.

When questioned by police at her home, police say Fieramusca couldn’t recall the name of the birthing center. When confronted by a Texas Ranger about her whereabouts on Dec. 12, Fieramusca allegedly denied being in Austin.

Authorities searched Fieramusca’s home and noted the “unmistakable odor of decomposing flesh” coming from her car’s trunk. Upon further inspection, they found Broussard’s body in the trunk and Margo in the home.

The search for Broussard and Margo was over.

RELATED: Kidnapped Baby Girl Is ‘In Very Good Health’ After Her Mom Heidi Broussard Was Found Dead

Fieramusca was arrested and charged with two counts of kidnapping and one count of tampering.

“Heidi had so many friends. Everybody loved her. We thought Magen loved her too,” Broussard’s mother Tammy previously told PEOPLE. “But evidently that wasn’t the case. She wanted Margo, is what she wanted.”

Fieramusca has not been charged with Broussard’s murder. Her attorney could not be reached for comment Tuesday.

It is unclear where Broussard died, however an autopsy determined her cause of death to be strangulation.