A Chicago man confessed to killing his girlfriend 's mother , whose body was found last month in a suitcase outside a hotel in Indonesia , police in Bali tell CNN . The girlfriend also confessed to being involved and trying to get rid of her mother 's body , police say . Heather Mack , 19 , and Tommy Schaefer , 21 , have been detained as suspects in the death of Mack 's mother , Sheila von Weise Mack , and `` it appears that the motive for the killing was because she was against Schaefer 's relationship with Heather , '' Bali police spokesman Hery Wiyanto told CNN . Formal charges are pending , as the investigation continues . What exactly happened in room 317 of the St. Regis Bali Resort and the exact role Heather Mack has is still under investigation , said Denpasar police Chief Djoko Hari Utomo . Evidence includes surveillance video of an argument between the couple and the victim at the hotel and of the two suspects entering and exiting the hotel room , according to Wiyanto . The badly beaten body of Sheila Mack , 61 , was wrapped in a blood-stained bed sheet and placed in a large hard-sided suitcase , Indonesian authorities said . The young couple allegedly put the suitcase in the trunk of a taxi outside the hotel on August 12 and went back into the hotel , telling the cab driver that they would be back , authorities said . After a lengthy wait , the cab driver noticed blood and contacted police . Authorities at the South Kuta station in Bali opened the case and found the body , police said . The daughter and her boyfriend were later found at another hotel about 15 kilometers ( 9 miles ) from the St. Regis . The couple 's St. Regis room was `` very messy , '' with clothes still inside , authorities said . The couple initially told police they had been taken captive at the resort by an armed gang , whose members killed Sheila Mack , but they escaped , CNN affiliate Trans TV reported .
Heather , 19 , and Sheila von , 21 , of Indonesia area confess , police say . They had been charged in the death of Mack 's mother , Mack Weise Sheila von . Motive was how mother `` was against Schaefer 's relationship with Heather , '' police say . Daughter was at the killing scene when her mother was killed , police say .