The FBI might arrest Heather Mack, who served seven years in an Indonesian prison for aiding in the 2014 murder of her mother, helping her boyfriend stuff the body in a suitcase at a Bali hotel, upon her expected return to the U.S. on a flight arriving at a Chicago airport Wednesday, her attorney says. 

One of Mack’s U.S.-based attorneys, Brian Claypool, tells Fox News Digital he participated in an emergency custody hearing Tuesday to prevent federal agents from separating Mack from her 6-year-old daughter, Stella, at the airport. He is fighting to at least allow the child to stay with Oshar Putu Melody Suartama, an Australian woman married to a Balinese man who has acted as Stella’s foster mother for the past five years while Mack was still incarcerated. The FBI plans to have Child Protective Services on standby at the airport Wednesday morning, Claypool said.  

U.S. federal authorities have since intervened to escort Heather Mack and Stella back to Chicago, Claypool said. Mack, Stella and the foster mother will ride on a flight together from South Korea that was expected to arrive at Chicago’s O’Hare International Airport at 9 a.m. Wednesday. 

BALI ‘SUITCASE KILLER’ TO RETURN TO CHICAGO FROM INDONESIA WITH DAUGHTER 

Upon touching down, Mack could be questioned for up to 24 hours without her attorney present or might be served with an arrest warrant for conspiracy to commit murder in connection to the killing of her mother, Sheila von Wiese-Mack, Claypool said. The FBI referred Fox News Digital to the U.S. Attorney’s Office for the District of Illinois. Federal prosecutors did not immediately return a request for comment sent Tuesday. 

"The deafening silence from the FBI is unnecessary, traumatic and borders on constitutional violations. They are playing Russian roulette with a 6-year-old’s life," Claypool said in a statement to Fox News Digital. "Once in foster care system in Cook County, the trauma imposed on Stella will be profound and life-changing. Stella will be with complete strangers in a new city let alone a new country." 

Mack’s legal team convinced a Cook County judge Tuesday to have Stella placed in the temporary custody of a private citizen of their choosing should Mack be taken into custody, Fox 32 Chicago reported. Claypool told Fox News Digital he had a plan in place until a few days ago to have Heather, Oshar and Stella stay in Los Angeles with a woman by the name of Diana Laroque as Stella would continue virtual learning at the school she attended while living in Indonesia. The Chicago Tribune reported the FBI ordered Mack to return to Chicago instead of Los Angeles as she had first planned. 

"They are inseparable. Stella loves Oshar like her own mom," Claypool told Fox News Digital via email. "The actions of the U.S. attorney and the FBI might jeopardize Stella’s stable and loving home. As Heather’s lawyer, I haven’t been contacted by anyone as to why federal law enforcement has hijacked Heather and Stella. Both she and Stella have constitutional rights to due process. No arrest warrant has been served on Heather by U.S. law enforcement so why is she being escorted to Chicago?"

What will happen between Mack and federal authorities when she steps off the plane remains to be seen, but von Wiese-Mack's brother recently told DailyMail.com that his niece's 10-year sentence for the killing of his sister was "a joke," as Heather Mack should have served closer to 40 years. 

The body of von Wiese-Mack, 62, was found inside the trunk of a taxi parked at the upscale St. Regis Bali Resort on the touristy Indonesian island in August 2014. Heather Mack, who was almost 19 and a few weeks pregnant, and her then-21-year-old boyfriend, Tommy Schaefer, were arrested a day later after they were found at a lower-scale hotel about 6 miles from the St. Regis.

Schaefer testified in court that von Wiese-Mack was angry at him when she learned about her daughter’s pregnancy. He said she insulted him and Mack, wanted her to get an abortion and strangled him in a heated argument before he struck her several times with a fruit bowl. Prosecutors said Mack helped stuff her mother’s body in the suitcase by sitting on it to enable Schaefer to close it.

Kia Walker, who is Schaefer's mother, and therefore Stella's paternal grandmother, is also fighting for custody of the girl upon her return to the U.S. 

"She's going to fight in court to see that she's able to spend time with Stella and to be an important part of her life as any grandparent would want," Walker's attorney, Mike Goldberg, told Fox 32. 

On Friday, Mack was released from Kerobokan Female Prison in Denpasar, the Bali provincial capital, where she served seven years out of her 10-year sentence after being granted an early release in August for good behavior. She was brought to an immigration office near Bali’s international airport, where she was expected to be reunited with her daughter, whom she had not seen for 20 months. After waiting days while waiting for her flight tickets and travel documents to be ready, she then was closely escorted by immigration officers to Bali’s airport for a flight to Jakarta.

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Schaefer received an 18-year sentence. Their daughter, Stella Schaefer, was born shortly before her parents were convicted in 2015. Under Indonesian law, she was allowed to live with her mother in her cell in Kerobokan female prison until she turned 2 years old, and Heather Mack gave custody of her young daughter to the Australian woman until her release from prison.

Two years after Mack’s conviction in Indonesia, the FBI filed a search warrant in January 2017 seeking to extract information from Mack’s cellphone as part of their ongoing investigation into the possible conspiracy to murder her Chicago socialite mother so Mack could access a $1.5 million trust fund set up after the 2006 death of her father, the famed jazz arranger conductor James L. Mack. 

Meanwhile, Schaefer’s cousin, Robert Bibbs, was charged in connection to the murder plot after federal investigators learned of his involvement by analyzing messages from Schaefer’s phone. In 2016, Bibbs pleaded guilty to helping plan the killing in exchange for $50,000 that Mack was expected to inherit and is serving a nine-year prison sentence in Michigan. 

The Associated Press contributed to this report.