No one's saying this officially, however I and others believe that's what it is.

A quick analysis:

The shooter is located just outside the capitol.

The shooter has targeted:

Black
White
Hispanic
Woman
Man
Old
Young

By that pattern, orientals should be on the lookout as well as cripples, because clearly the shooter(s) are targeting "a cross-section of America"

A suicidal maniac's rampage is short and often ends turning the gun on himself.

This shooter is cold and calculating and the crimes are occuring over a longer period of time than someone who "snaps".
He hasn't "fled" but is clearly pursuing an "agenda" wherein risk of capture is part of the mission.

Profile:
Religion: Muslim
Age: 18-50
Sex: Male
Weapon: .223 Hunting Rifle - likely purchased in the region.

Check out the motels, where cars and people can come and go unhindered, stake out the cripples and the orientals' regional hangouts. Check out all muslim neighborhoods for leads.

The disregard for ALL life indicates its not a conventional psycho - but a religious fanatic.

All things point to an activated sleeper cell - creating terror on the cheap.

SDAI-Tech1