Christie White, 46, smiles thinking of her last peaceful memory. It was a girls’ weekend. It was Sunday night. Christie and Dani and Beth were hanging out in the perfect late-summer weather under glimmering Las Vegas lights with some cocktails, and their favorite country bands.

The volunteer psychologists and counselors have been pouring into this grieving city, so fast that a state official says the supply far exceeds the demand for crisis counseling.

We often think of first responders mainly as police, fire and emergency-medical professionals. In Las Vegas on Monday, NPR's Eric Westervelt found a small volunteer army of mental-health professionals, trauma counselors, psychiatrists and social workers who quickly fanned out to help some of the thousands who had witnessed the massacre up close.