Lop the guys finger off, put in evidence bag along with phone, problem solved
Now, if the phone had been an iPhone 5S rather than a 5C, that's probably exactly what they would have done, him being dead and all.
If the phone has been turned off, or it's been can't remember but either 24 hours or 48 hours with only finger print access then typed in access is needed again. Plus finger print access can be turned off in settings. If they were planning forward as they obviously we're with the crushing of two phones they would've thought of that.