A 22-year-old Tucson man is in custody in connection with the shooting of Rep. Gabrielle Giffords and 18 other people at a Tucson mall.
Jared Lee Loughner is being held after Giffords was shot Saturday at an event in Tucson.
Multiple search warrants are being served in the investigation, said Pima County Sheriff's Department spokesman Rick Kastigar.
Giffords is in critical condition after being shot through the head, according to UMC where Giffords is being treated.
At least six people were killed - including a 9-year-child - and 13 injured when an assailant sprayed bullets into an area where the lawmaker was meeting with constituents.
Four victims were taken to St. Mary's Hospital, three with gunshot wounds. All are in stable condition.
These officials, who asked to remain anonymous, said one of the victims died soon after the attack, and others were taken to University Medical Center.
An aide from Giffords' office was one of those killed, reports the Associated Press.
The FBI and local law enforcement are investigating the attack, which took place while Giffords was greeting constituents outside a grocery store.
The shooting took place at a "Congress on Your Corner" event at about 10 a.m. at the Safeway on Ina and Oracle, Pima County Sheriff's Department spokesman Jason Ogan said.
In March, hours after Giffords voted in favor of health care reform, the front door of Giffords' Tucson office was shattered, also a side glass panel.