What a freakin' creep...
...just adds to the impression I have gained in the last couple of days that there are MANY among the male species who have more in common with a donkey's butt than the human race...
Unfortuantely, there are just as many woman do the same thing and worse, to men.
It's across the board, but yes, what he did is so low and nasty.
I think your friend should contact the police too - it's not always too late to regain what's yours and have the criminal punished for what he did.
$600 is a lot of money and if he took other stuff too, it's important to let him know he won't get away with it.