JAKARTA, Indonesia (CNN) -- The cabbie probably thought nothing of it when the young couple left their large hard-sided suitcase in the trunk of his car and went back into the five-star hotel.
They said they needed to find the other person they were with and to pay their bill.
But after a lengthy wait, the young man and woman still hadn't returned. Puzzled, the driver called hotel security.
The suitcase in the trunk looked very odd. It was wrapped in a bedsheet. Then the cabbie saw blood.
When authorities at the South Kuta station in Bali, Indonesia, opened it, they found inside the badly beaten body of Sheila von Weise Mack, wrapped in a blood-stained bedsheet.
Two smaller suitcases were found in the St. Regis Bali Resort garden. Both contained hotel towels with blood on them, according to police.
Mack, 62, of Chicago, had been staying at the posh St. Regis with her 18-year-old daughter, Heather Mack, and the daughter's boyfriend, Tommy Schaefer.
The daughter and her boyfriend were later found at another hotel about 10 kilometers (6 miles) away. The couple's St. Regis room was "very messy," with clothes still inside.
The couple told police they had been taken captive at the resort Tuesday by an armed gang, whose members killed Sheila von Weise Mack, but they escaped, CNN affiliate Trans TV reported.
Djoko Hari Utomo, police chief of Denpasar, the capital of Bali, said the pair were taken into custody but said they cannot be described as suspects at this point of the investigation.
According to Indonesian law, police can keep the couple in custody for up to 24 hours before they are named as suspects. If named, they can be held up to 20 days.
A doctor who examined the body said that judging by the bruises and other wounds, Mack was struck on the face and other parts of her head with a blunt object. She also had a gash on her forehead.
Dr. Ida Bagus Putu Alit told CNN that there was evidence -- a broken fingernail and bruises on both wrists -- of an apparent struggle.
He said Mack likely had been killed eight to 12 hours before he received the body Wednesday afternoon.
A spokesman for the St. Regis, where rooms go for $500 to $8,200 a night, said the hotel staff is "deeply saddened" by the incident and is doing all it can to assist investigators.
A profile of Mack published by The Caxton Club of Chicago (PDF) says she worked for Edward M. "Ted" Kennedy, the late U.S. senator from Massachusetts, and studied with Pulitzer Prize-winning writer Saul Bellow for 10 years.
A man who said he was her neighbor confirmed Mack moved to Chicago a year ago from the affluent suburb of Oak Park, Illinois, according to CNN affiliate WGN.
"She was very much involved in the arts so you would see her at concerts, you'd see her at lectures," Allen Parchem told the station. "I knew that she had a very active arts life downtown too, attending events, so with the move to downtown I think she was hoping to be even more apart of that scene."
CNN's Roger Clark reported from Jakarta and Steve Almasy reported and wrote from Atlanta. CNN's Eric Marrapodi, Joshua Berlinger, Brian Walker, Shawn Nottingham, Jethro Mullen and journalist Tasha Tampubolon contributed to this report.