From The Australian Pocket Oxford Dictionary (4th ed):
spree n. colloq 1 lively extravagant outing (shopping spree). 2 bout of fun or drinking etc. [origin unknown]
Trigger warning.
You can almost hear them, can’t you? Guffaw guffaw … it’s about shop assistants … you know, it’s almost like he went shopping … you know, like a spree or something! Guffaw guffaw.
Actually, that’s probably giving them too much credit – it was probably much more unthinking and unconscious than that.
Just another example of the trivialisation of sexual offences in our community.
Wallaby 
Actually, the associations that pop into my head seeing the word spree used in that context are to do with shooting sprees, which seems an entirely appropriate use of the word.
From AskOxford.com
spree
• noun a spell of unrestrained activity of a particular kind.
But I don’t doubt the colloquial usage would be evoked for some.
I’m with mimbles on this. I don’t know if it’s only an American usage, but “killing spree” and “shooting spree” are decades-old terms. “Spree killer” is even a term used by the FBI to distinguish someone who goes on a homicidal tear (as distinct from serial killers).
Maybe you’re both right – I admit that I hadn’t thought of that usage.
However. I still think it’s off to use the word in the context, as I still think there’s a really strong link to “shopping spree”. It was my first thought, and while it’s clearly not the only possible first thought, I’m quite sure I’m not the only one who picked up on it.
While you may both be absolutely correct that the usage you have both indicated is the one intended, it’s not like it’s the only available word – and while it’s not unknown in Australia, it hasn’t hit my consciousness as being used that much in the popular media. I’m thinking we tend to use “rampage” instead. This isn’t quite a “rampage”, but the media is not exactly known for its underuse of hyperbole.
But of course, this is based on my own recollection, which is hardly the best way to do research ;) It may be that we do use it a lot and I just haven’t noticed.
I still think it’s incredibly insensitive and just plain wrong to use it in this context, whatever the intention – and even if it is used frequently in Australia in the context of violent crime.