This is what I can't understand, though. She was 78 and she was tiny. Mentally and intellectually, she was very strong and determined; but physically, any young bloke could very easily have got her out of the way and rendered her powerless for the time it took to steal her possessions without having to actually hurt her.
Leaving aside the fact that burglars obviously couldn't care less about their victims, it's a very sad indictment that he should have such confidence that turning a burglary into a murder would have negligible additional negative consequences for himself.