Originally Published: 04 FEB 23 11:14 ET

By Melissa Alonso, CNN

(CNN) -- The Texas woman accused of killing Heidi Broussard and kidnapping the victim's infant has been sentenced to 55 years in prison after pleading guilty to the 2019 murder, according the Travis County District Attorney's Office.

Magen Fieramusca, 37, was arrested more than a week after Broussard's body was discovered in a vehicle at Fieramusca's residence. The baby was found, unharmed, in Fieramusca's home.

Broussard, 33, and her newborn daughter, Margot Carey, went missing on December 12, 2019, after Broussard dropped her son off at an elementary school.

As part of the plea agreement, "Fiermusca waived her right to appeal, meaning that her cases will not remain open for post-conviction litigation after sentencing," Travis County District Attorney José Garza said in a statement on Tuesday.

"We are hopeful that this outcome will bring some closure to the Broussard and Carey families and help them continue their healing process," Garza said. "This outcome will save the families from having to endure the difficult post-conviction litigation process."

Fieramusca's attorney, Brian Erskine, said In a statement to CNN affiliate KPRC that the agreement was the best resolution to avoid possible appeals.

"After considerable discussion, in conjunction with significant compelling mitigation related to Ms. Fieramusca and the possible appellate issues related to the search of her residence, both parties feel that this is the appropriate resolution," Erskine said.

"I imagine many have questions that will never be adequately answered, nevertheless, I hope that this plea brings some closure to this family's great loss."

Fieramusca was indicted in 2020 by a grand jury in Travis County. She was accused of kidnapping Broussard and the baby and asphyxiating Broussard.

At the time, Fieramusca's bond was set at $1 million for the capital murder charge.

Margot was reunited with her father and brother.

Friends for more than a decade

Broussard and Fieramusca had been friends for more than a decade, Broussard's boyfriend Shane Carey told police, according to an arrest affidavit. They met while attending the Texas Bible Institute in Columbus, Texas, the document said.

Fieramusca had said she and Broussard were pregnant at the same time, according to the affidavit. Carey told investigators that "both women had spoken about the possibility of delivering on the same date," according to the affidavit.

It's unclear if Fieramusca was ever pregnant.

But, the affidavit said, she convinced friends and an ex-boyfriend that she had given birth and then tried to pass off Broussard's child as her own.

Surveillance video taken by a neighbor showed Fieramusca's vehicle in the parking lot of Broussard's apartment complex on the day of her disappearance, the affidavit said. A resident of the apartment complex told investigators that she saw a woman with a small infant get into the back seat of the vehicle before it sped away.

FBI agents searching for Broussard and her daughter followed Fieramusca's ex-boyfriend Christopher Green as he left their shared home in Houston and approached him as he left a Target store with baby clothes and formula, the affidavit said.

When they showed him a flier with pictures of the missing mother and child, he replied, "That's the baby at my house," the affidavit said.

Green said he believed that Fieramusca had been pregnant with his child, the document said, and Fieramusca told him that she had given birth.

Fieramusca told investigators that she had given birth at a birthing center in The Woodlands, an area north of Houston, and brought the baby home the same day. When questioned by investigators she could not recall the name of the center, the affidavit said.