At the time, Giffords' press secretary C.J. Karamargin said the office had received many phone calls with "nasty and rude and hateful comments" from opponents of the health care bill.
Recently Giffords, who supports gun rights, has been receiving angry letters from anonymous sources, ranting about the supposed national gun registry and border control.
One letter received on Dec. 15 addressed to "giffords, obama, mccain and sen. Jon kyl" got personal on the topic of U.S. Border Patrol Agent Brian A. Terry, who was killed in a late night shootout at the U.S.-Mexican border.
"Brian a Terry's blood is on your hands! How many more legal residents of the USA have to die before the border is CLOSED??? Obama I call you out! CLOSE THE DAMN BORDER NOW! Quit pandering to illegals!," the letter read.
Giffords has a reputation as a political rebel. She voted with the Democratic party about 40 percent of the time, according to Congressional Quarterly, though she supported her party's effort to pass a landmark health reform law.
She was also one of a handful of Democrats who did not vote for Nancy Pelosi for speaker of the house, during the recent Democratic leadership elections after Democrats lost their majority in the House last November.
At a candlelight vigil Saturday night, authorities found a suspicious package outside Giffords' office and later detemined it was non-explosive, the Associated Press reported.
Police said the item looked like a coffee can and contained writing which was not disclosed to the media, according to the Associated Press.
ABC News' Rich Esposito, Pierre Thomas, Jack Date, Jason Ryan, Gina Sunseri, Ross Eichenholz, Toni Wilson, Desiree Adib, Sherisse Pham, Amy Walter, Leezel Tanglao and the Associated Press contributed to this report.