The woman murdered in Bali and stuffed into a suitcase died from asphyxiation after a blunt-force blow to her nose blocked her airway, an autopsy has found.
The news came as it emerged that an agent from the American Federal Bureau of Investigation had also flown to Bali to assist local police.
The head of forensics at Bali's Sanglah morgue said another blow from an as-yet unidentified weapon had also smashed one of the vertebrae in former Chicago resident Sheila Von Weise-Mack's neck.
Dr Ida Bagus Putu Alit said death came quickly to the 62-year old, whose teenage daughter is now in custody under suspicion for the murder.
Heather Mack, 19, and her boyfriend Tommy Schaefer, 21, face the death penalty if convicted of premeditated murder, the charge the police are now considering.
Alit said Mack had died between when she was last seen on CCTV footage at the five-star St Regis Bali hotel at about 3am on Tuesday, and 8am.
Other injuries to her left arm were consistent with trying to defend herself from the blows.
Heather Mack has claimed she is pregnant with an ectopic pregnancy, which may not show up on conventional, over-the-counter tests, and police are still waiting on the results of physical tests conducted on Friday.
Also on Friday, an officer from the US Federal Bureau of Investigation arrived to assist the Bali police in their investigation.
Head of Denpasar police Djoko Hari Utomo said the FBI were in Bali to "expedite the police investigation". He said the involvement of Mack and Schaefer in any criminal activity in the United State was still "subject to ongoing investigation".
"We are making no connection to anything in America. We're just dealing with what happened here ... We don't know what happened there," Djoko said.
The pair are being kept separately and have not yet been formally questioned until they have local legal representation. However, Mack has appointed an American lawyer, Michael Elkin, who says his client is innocent.
Bali police chief Benny Mokalu said last week that there was enough evidence, including CCTV footage, fingerprints and items found at the murder scene which "all points to them as the perpetrators."
Von Wiese Mack's murderers stuffed her body into a grey suitcase, wrapped that in a hotel bed sheet and then loaded it into a pre-ordered taxi.
- Sydney Morning Herald