A hate attack. Sounds about right.
I feel the need to point out that judging an entire group of people, regardless of the given group or ones inclusion therein, based on the actions of a number of units less than the entirety of the given group is the cause of hate crime in general.
In regards to this case itself, I do not personally feel that enough evidence has been provided to me to convict this man of a hate induced crime, but an investigation into that possibility is certainly called for.
I'm not entirely sure if your second sentence is intended to be outlining an alternative scenario, though if not I would point out that this article says nothing regarding an affair. The only facts established regarding the nature of the relationship is that they are both romantically involved with one another, and both female.