Heather Mack has acknowledged she is under threat of prosecution in the United States, citing an “ongoing federal criminal proceeding” in a fresh round of court filings this week.

The 21-year-old Chicagoan, imprisoned in Indonesia, made the claim as she asserted her Fifth Amendment right against self-incrimination in a legal battle scheduled to return to a Cook County courtroom on Friday. She said she would continue to do so “until she is no longer under the threat of criminal prosecution in America or Indonesia.”

The body of Mack’s mother, Sheila von Wiese-Mack, was found in August 2014 in a suitcase in the trunk of a taxi outside the St. Regis Bali Resort. Mack had been vacationing there with her mother before Tommy Schaefer, the father of her yet-to-be-born child, joined them.

Mack and Schaefer were later convicted in Indonesia for their roles in von Wiese-Mack’s slaying. Schaefer, now 23, was sentenced to 18 years in prison for beating the socialite to death with a fruit stand, and Mack was sentenced to 10 years for helping.

However, court records in Chicago show federal prosecutors launched an investigation into von Wiese-Mack’s murder shortly after she turned up dead. Schaefer’s cousin, Robert Ryan Justin Bibbs, has since pleaded guilty in federal court here for helping plot the murder. He is set to be sentenced in May.

RELATED:
No way Heather Mack’s mom murdered her dad, aunt says
Heather Mack’s confession may not hold up
In videos, Heather Mack confesses to mother’s murder in Indonesia

Two weeks ago, Mack appeared to give a stunning confession to her mother’s murder in a series of videos on YouTube, absolving Schaefer of wrongdoing. She claimed she plotted her mother’s murder because she had discovered von Wiese-Mack had killed Mack’s father during a family vacation to Greece. Mack’s aunt has called that claim a lie.

“I made it up in my heart, in my mind, my soul, in my blood, in the oxygen running through my body that I wanted to kill my mother,” Mack said.

But evidence outlined by federal prosecutors in Chicago appear to undermine Mack’s claims, and her lawyer later said the videos were recorded under pressure. Mack’s attorney claims she had been reading words written by Schaefer.