An Australian judge has rejected attempts by police to use step data from an iPhone’s health app to prove that a murderer was responsible for a shooting.
Last month, NSW Supreme Court Justice Sarah McNaughton struck out a smartphone data report as evidence in the case of Bahra Youseff, who was found guilty of murdering Adnan Salameh last week.
In a detailed explanation for the decision published this week, McNaughton laid out why she deemed a report about the smartphone’s step data as inadmissible due to concerns about its accuracy and usefulness, believing that it was more likely to mislead than to inform.
The prosecution had included the iPhone step data as part of its circumstantial case that Youseff was in the vicinity of Salameh when Salameh was murdered in his home at approximately 2.35am on November 30, 2020.
Other evidence included mobile phone radio tower signals showing Youseff’s phone was nearby, and a speeding ticket issued to Youseff for speeding after the incident.
A report prepared using smartphone data extraction company Cellebrite’s software found that Youseff’s iPhone 8 and iPhone 11 Pro showed identical data about steps recorded between 2am and 3am on the night of the murder.
While the prosecution didn’t rely on the specific distances recorded, it did claim that “the health application data record[ed] movements on 30 November 2020 around the time of the shooting”. No expert witness was called to explain what was captured in the report, which was instead left to be interpreted by a NSW police officer.
McNaughton relied on a 2019 scientific paper about the forensic use of Apple Health data to raise a number of concerns about the interpretation of the data.
Among her issues was the fact that this study found that iPhone step data is only useful in combination with specific circumstances. For example, if you have proven that the iPhone holder was walking or running at the time and not, say, in a car that is going over speed bumps being registered as footsteps. It also found that the iPhone distance tracker based on the number of user steps could be off by as much as 30-40%.
Additionally, the prosecution’s report lists the data retrieved from the device in three entries of steps that were 11 minutes apart (“68 steps were taken covering 46.58 metres at 2:24:52am … 71 steps were taken covering 93.68 metres at 2:35:15am”). McNaughton inferred that the 11 minute interval was a result of the data collection and not because there were three separate bouts of walking, meaning the exact time of the steps could not be known.
Even if those concerns about the data did not explicitly disqualify it due to various sections of the Evidence Act, McNaughton stated, their cumulative effect was that there was a greater danger that the iPhone step data report would mislead rather than inform the case.
iPhone step data has been successfully admitted into evidence in court cases around the world, including a 2018 German murder trial and a 2023 double murder trial in South Carolina. Other types of data recorded by Apple’s Health app have also been utilised, including heart rate data from a victim to ascertain the time of an attack. Despite Apple’s cat-and-mouse game with software developers who try to crack into its devices, companies like Cellebrite have still been able to access data from all but the most recent iPhones.
Despite the iPhone step data decision, Yousseff was found guilty on a charge of murder by a jury and will face a sentencing hearing on November 12.
