The Congress on Your Corner event on Saturday morning, Jan. 8 in Tucson, Arizona was at least the second such constituent event hosted by U.S. Rep. Gabrielle Giffords that was attended by Jared Lee Loughner, the 22-year-old Tucson resident who is charged by federal authorities with shooting Giffords, and killing U.S. District Judge John Roll and Gabriel Zimmerman, a Giffords' aide, according to the FBI.

In a sworn affidavit that accompanied the criminal complaint filed Jan. 9 by federal officials against Loughner,  FBI Special Agent Tony Taylor reported that federal agents, executing a search warrant at Loughner's residence on North Soledad Avenue, recovered a number of documents from a safe.

One of the documents was a letter addressed to Loughner from Congresswoman Giffords, on Congressional stationery, dated August 30, 2007, thanking him for attending a 'Congress on your Corner' event at the Foothills Mall in Tucson, according to Special Agent Taylor.

The event was held on Saturday, Aug. 25, 2007, from 10 a.m. to noon, for the purpose of Giffords explaining proposed changes to Medicare. Giffords had recently voted for the Children's Health and Medicare Protection Act, which provided new funding for children's health insurance.

Along with the letter from Giffords, authorities recovered an envelope from the safe with handwriting on the envelope stating 'I planned ahead' and 'My assassination' and the name 'Giffords,' and what appeared to be Loughner's signature, Taylor's affidavit said.

Pima County Sheriff Lawrence Dupnik said this morning that Loughner specifically targeted the Congresswoman.

We have eyewitness testimony and documents to prove that, Dupnik said.

The federal indictment, which concerns itself with employees of the federal government, charged Loughner with two counts of murder, for the killing of Roll, 63, and Zimmerman, 30, two counts of attempted murder regarding Giffords' aides Pamela Simon and Ron Barber, who were assisting her at the event, and one count of attempted assassination of a Member of Congress.

Loughner, who is in federal custody, is scheduled  to make his initial appearance in court at 2 p.m., Mountain Time, today before  U.S. Judge Lawrence Anderson in Phoenix.  The court will set dates for a preliminary hearing and a detention hearing, authorities said.

Judy Clarke, the attorney who defended Theodore Kaczynski, aka the Unabomber, has agreed to represent Loughner, according to reports.

 Four other people were killed in Saturday's massacre outside a Safeway supermarket on Oracle Road in Tucson -- Phyllis Schneck, 79, Dorothy Morris, 76, Dorwan Stoddard, 76, and Christina Taylor Green, 9. At least 11 others were injured in the shooting. Giffords, Simon, Barber and two other victims remains in critical condition at Tucson's University Medical Center.

Charges by local and state authorities are expected to be filed shortly.

Giffords, 40, was shot at point-blank range in the left side of the head. Authorities say the wound was a through and through, meaning the bullet went through the left side of the head and exited. She has undergone surgery and physicians are viewing her condition with guarded optimism.

Judge Roll, according to published reports, was not a scheduled guest but had decided to attend the event to chat with the Congresswoman about the large federal court caseloads in his district. The nine-year-old victim, Christina Taylor Green, was the granddaughter of former Major League Baseball manager Dallas Green. She was born on Sept. 11, 2001 and, for that reason, she was one of 50 babies featured in a book called Faces of Hope.