Fox News reported Sunday morning that an internal Department of Homeland Security memo obtained by the network indicated that suspect Jared Lee Loughner, 22, is "possibly linked" to an anti-Semitic, white supremacist group.
The DHS memo called the group American Renaissance "anti-government, anti-immigration, anti-ZOG (Zionist Occupational Government), anti-Semitic." The information reportedly came as Loughner's computer and personal effects were searched in the shooting investigation.
The group's leader told Fox that they had no record of Loughner being on the subscriber list or attending events.
Rep. Gabrielle Giffords (D), who attends a Reform synagogue in Tucson, is Arizona's first Jewish congresswoman.
The Blue Dog Democrat is pro-gun rights and has worked to get more National Guard troops and Border Patrol agents on the Mexico border.
In August, Giffords called on the Senate to interrupt its summer recess to pass a bill that approves another $600 million for border security.
Loughner posted a series of ramblings on online sites that experts have indicated point to possible psychosis.
He is scheduled to appear in court via video on Monday, facing counts of killing six, including a federal judge, and wounding 13. He is reportedly not cooperating with law enforcement.
Authorities had been searching for a person of interest who may have acted as an accomplice to Loughner, a white male in his 40s or 50s. The Pima County Sheriff's Department released a still from a surveillance video of the man who appeared to enter the Safeway next to the shooting with Loughner.
However, the man turned out to be a cabbie who had driven Loughner to the scene and went into the store with the suspected gunman to get change.
This post was updated at 9:30 p.m.