I think the reason Rihanna was in the news was that the incident happened the night before or of the Grammy's, which they were supposed to attend together.

Not just attend but perform which was why Justin Timberlake was suddenly called on to get up there with Al Green.

Sadly, the LA Times used this as their justification of releasing Rhianna's name to the world before a lot of information had been completely verified. I sat there thinking, "Don't they keep the victim's name under wraps in cases like this?"