They don't say if it was an Apple or Android device. Either way -- that was fast. I wonder what happened here? Did the suspect not have encryption turned on? Using an older phone with known vulnerabilities? Is the FBI sitting on some 0-days?
Couldn’t it be as simple as a face recognition unlock?
There’s an option on iPhone’s FaceID to require eyes open and looking at phone to unlock, but this might have been deselected. Or it could be subverted.