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

Virginia Tech Massacre: Gunman's Identity Coming to Light

Update: 9:45 p.m. (Revised)

Sources: FOX News/ABC News

Michael Sneed of the Chicago Sun Times is reporting that the Virginia Tech murderer was a 24 year old Chinese national who arrived in the US, on a student visa, this passed year.

The 24-year-old man arrived in San Francisco on United Airlines on August 7 on a visa issued in Shanghai, the source said.

His name has not yet been released, but more information is coming to light as the hours pass.
Before opening fire in Norris Hall, he first went to Randolph Hall. At this point, there are no reports that he harmed anyone there. The gunman murdered dozens of students before turning the gun on himself. Local law enforcement say that a .22 caliber pistol and a 9mm handgun were recovered at the scene.
No identification was found on the gunman's body, police said. Eyewitnesses described him as an Asian male about 6 feet tall. He apparently shot himself in the head after the killings; part of his face was missing when his body was found.

VICTIM STATUS: Most of the victims have been identified. Many of the bodies of those who died in Norris Hall have been removed from the building. Death notifications are being handled right now.

My question -- Why has the gunman's vehicle not been located yet?