Heather Mack, 19, and her 21-year-old boyfriend Tommy Schaefer have been charged with murder of Heather's mother. Both could be executed by firing squad if found guilty by the Indonesian courts, according to The New York Daily News.

Death row prisoners are executed by firing squad in Indonesia. The inmate is taken to a field and shot in the chest by 12 gunmen.

Police said the vacationers from Illinois killed Sheila von Wiese-Mack, 62, after an argument at the St. Regis Bali where they were staying. Investigators have not yet determined how Wiese-Mack died, but her half-naked body was found wrapped in a bedsheet inside a silver suitcase, according to NBC News.

Mack and Schaefer allegedly brought the suitcase containing the body down to a taxi cab on Tuesday. The couple told the driver they needed to get more bags, but they quickly checked out and left the hotel through a back door. The driver waited for them to return for two hours before he noticed blood on the suitcase and drove it to a police station where the body was then revealed.

The two refused to cooperate with police during the two days of questioning following their arrests. Mack allegedly told officers she is pregnant and needs to be brought back home for medical treatment, according to news.com.au. She has undergone a pregnancy test at a local hospital and the results are still pending as of Friday.

Mack and her mother seem to have had a rough relationship. Between January 2004 and June 2013, police were called to the family's home 86 times on domestic violence and theft calls. All of the domestic violence calls involved Mack and Wiese-Mack, The New York Daily News reported.