Police can access a trove of data from smart speakers found at crime scenes that could be invaluable in solving murders or burglaries, say researchers. Data on recently recognised faces, internet searches and any voice commands received could be extracted even without the owner’s permission or assistance from the manufacturer.

Jona Crasselt and Gaston Pugliese at the University of Erlangen-Nuremberg in Germany decided to explore how much information can be pulled from these devices after seeing news coverage of Amazon refusing to…