Law enforcement radio traffic moments after Rep. Gabrielle Giffords was shot describes a dispatcher urgently relaying first word of the attack to Pima County sheriff's deputies.
The dispatcher says "a caller's reporting a shooting, a semiautomatic weapon. He shot at people."
In the tapes released Thursday, the dispatcher goes on to say "we have a caller who believes that Gabrielle Giffords was shot. That's, uh, multiple victims."
The dispatcher then says "customers have tackled the suspect. They are holding him down."
Later, a deputy is heard calling for ambulances: "There are multiple victims."
Authorities earlier released 911 tapes of Saturday's shooting in a Tucson-area Safeway parking lot, which left six people dead and 13 wounded, including the lawmaker.
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