(CNN) There's a new kind of first responder to some crime scenes in Milwaukee, Wisconsin: musicians.

Toting their violin, viola and bass cases, they set up among the investigating police and reporters scrambling to get the story after a shooting. And soon the mournful sound of a spiritual, like "Sometimes I Feel Like a Motherless Child," fills the night.

The Black String Triage Ensemble , with seven members ranging in age from 11 to 70-something, has played at more than a dozen crime scenes this summer, according to CNN affiliate WISN

Dayvin Hallmon founded the volunteer group of string musicians this year. The group, made up of African-Americans and Latinos, aims to be a "healing force" for communities coping with violence, he said.

The musicians play not so much for the immediate victims and their relatives. For those people, "the trajectory of healing, and dealing with that, is so much longer" than the music can span, Hallmon said.

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