Murder at VT's West Ambler Johnston Dorm

Update: 10:28 p.m.
The female student killed at West AJ was shot in the back of the head -- reportedly by her estranged boyfriend.
Students are saying there was an early morning argument between the female student and her boyfriend. It's not clear whether the boyfriend had been in the room all night, or had arrived early this morning. The as yet unidentified female student's Resident Advisor (RA) entered her room in an attempt to mediate and hopefully calm the situation. Within minutes, the young lady lay dead in the floor of her dorm room. Her RA Ryan "Stack" Clark was shot in the neck. He later died.
The Blacksburg Police Department was lead to believe that the killer was a "greasy haired" guy who was driving an old pickup truck with farm plates.

Some media outlets are saying that the perpetrator murdered his girlfriend, then hid out for almost two hours before heading over to first Randolph Hall, and then Norris Hall -- going on a shooting rampage in the latter. {I don't buy that idea, at all.}

Question - Were there TWO shooters?
1) An angry boyfriend killing his girlfriend & her RA at the West Ambler Johnston dorm
2) Chinese national, who was likely not a VT student, committing massacre in Norris Hall