Full reports hints that they can already read data from iPhones too:
Highlighting the potential value of data from mobile apps, a recent murder
investigation in Germany utilized metrics from the apps on individuals’ phone. In
that case, Apple’s iPhone health app activity record stated that the suspect was
“‘climbing stairs,’ which authorities were able to correlate with the time he would
have dragged his victim down the river embankment, and then climbed back up.
I'm not sure if the data comes from physical access to the phone or from asking service providers.
Highlighting the potential value of data from mobile apps, a recent murder investigation in Germany utilized metrics from the apps on individuals’ phone. In that case, Apple’s iPhone health app activity record stated that the suspect was “‘climbing stairs,’ which authorities were able to correlate with the time he would have dragged his victim down the river embankment, and then climbed back up.
I'm not sure if the data comes from physical access to the phone or from asking service providers.