Officers responding to reports of the mass shooting in Tucson Saturday can be heard in audio recordings released today pleading for "every ambulance" in the area to respond to the gruesome scene.
"We need multiple med units," an officer, who does not give his name, says on the radio transmissions released today by the Pima County Sheriff's Office. "Get every ambulance we have out here."
"There's a man with a semi-automatic," says another unidentified officer. "We have a caller who believes Gabrielle Giffords was shot. It sounds like many people are shot. I'm counting at least 10."
That man later is identified as Jared Loughner, the 22-year-old now accused of the shooting that killed six and injured 14, including Rep. Giffords, D-Ariz.
Another officer says over the radio, "Customers have tackled the suspect. They have him held down at the Safeway."
The Pima County Sheriff's Department also announced today that a man walking his dog near Loughner's house found a black bag.
It was not immediately clear whether the black bag is the same one Loughner was seen removing from the trunk of his car the morning of the shooting.
"He's telling us that in the bag is what appears to be ammunition and some items from what he described to us as from a local Wal-Mart," said R.J. Kastigar, the bureau chief at the Pima County Sheriff's Department.
Police also know Loughner bought ammunition from a Walmart on the morning of the shooting.
"This is one of the critical pieces of evidence we've been looking for," Kastigar said.