TUCSON, AZ & SANTA FE, NM (By Marc Lacy and David M. Herszenhorn, NYT) November 15, 2010 ― Prosecutors accused Jared Lee Loughner, a troubled 22-year-old college dropout, of five serious federal charges on Sunday, including the attempted assassination of a member of Congress, for his role in a shootout that left 20 people wounded, six of them fatally, on Saturday morning.

Court documents filed in the U.S. District Court in Phoenix indicated that evidence seized from Mr. Loughner’s home showed he had planned to kill Representative Gabrielle Giffords, who was in critical condition with a gunshot wound to the head. Found in Mr. Loughner’s home, F.B.I. special agent Tony M. Tayler Jr. said in an affidavit supporting the charges, was an envelope with the handwritten words, "I planned ahead," "My assassination," and "Giffords."

The details of the envelope were not disclosed.

The court documents say that Mr. Loughner purchased the semiautomatic Glock pistol used at the shooting at Sportsman’s Warehouse in Tucson on Nov. 30. The documents also indicate that the suspect had previous contact with the congresswoman. Found in the same safe was a letter from Ms. Giffords thanking Mr. Loughner for attending a 2007 “Congress on Your Corner” event, like the one she was holding on Saturday morning when she was attacked.

Along with being accused of deliberating trying to take Ms. Giffords’ life, Mr. Loughner was charged with the killing and attempted killing of four United States government officials, among them U.S. District Judge John M. Roll, who was killed; a congressional aide, Gabriel Zimmerman, who was also killed; and two congressional aides, Pamela Simon and Ron Barber, who were wounded.

The authorities released 911 tapes of the minutes after the shooting in which caller after caller, many of them out of breath, dialed in to report multiple shots being fired, and people falling, too many to count.

The director of the Federal Bureau of Investigation, Robert S. Mueller III, who traveled to Tucson from Washington to oversee the shooting investigation at President Obama’s request, said at a news conference that an intensive investigation was underway to determine ``why someone would commit such a heinous act and whether anyone else was involved.”

Early Sunday, the authorities released a photograph taken from surveillance video of a possible accomplice in the shooting. But the man later contacted sheriff’s deputies, who determined that he was a taxi driver who dropped the suspect at the mall where the shooting took place and then entered the supermarket with him when he did not have sufficient change.

Ms. Giffords, an Arizona Democrat, remained in critical condition on Sunday but has been able to respond to simple commands, and her doctors described themselves as “cautiously optimistic.”

At a news conference at University Medical Center, the congresswoman’s doctors said that she was the only one of the victims of Saturday’s shooting to remain in critical care at the hospital. They said that she was lucky to be alive but would not speculate about the degree of her recovery, which they said could take months or longer.

“Overall this is about as good as it’s going to get,” said Dr. Peter Rhee, the chief of trauma surgery at University Medical Center, where Ms. Giffords was brought by helicopter from the shooting scene outside a supermarket north of Tucson. “When you get shot in the head and a bullet goes through your brain, the chances of you living are very small and the chances of you waking up and actually following commands is even much smaller than that.”

Dr. G. Michael Lemole Jr., the chief of neurosurgery, who operated on Ms. Giffords, said that the bullet had traveled through the entire left side of her brain “from back to front” but said that it had not crossed from one side of the brain to the other, nor did it pass through some critical areas that would further diminish her chances of recovery.

The doctors said Ms. Giffords, 40, was in a medically induced coma but that they had awoken her several times to check her responsiveness. While the doctors described themselves as extremely pleased with the progress of her treatment, they cautioned that it was too soon to make any predictions. “This is very early in our course,” Dr. Rhee said. “We don’t know what’s going to happen, what her deficits will be in the future or anything like that.”

The doctors said that brain swelling and other complications still posed large risks in the days ahead.

Darci Slaten, a spokeswoman for the medical center, said the congresswoman’s husband, the astronaut Mark E. Kelly, was with her, as were her parents and two stepchildren.

As the doctors provided the update on Sunday, law enforcement authorities tried to piece together what prompted a troubled young man to go on a shooting rampage here that killed six people, including a federal judge, and wounded Ms. Giffords and 13 others.

At the news conference, Sheriff Clarence W. Dupnik of Pima County described a chaotic scene of terror and heroism as the shots rang out. He said one woman who was injured in the shooting fought to wrestle a magazine of ammunition away from the suspected gunman as he tried to reload. He succeeded in reloading, the sheriff said, but was then tackled to the ground. Officials, who did not name her, said the attack could have been more devastating had she not tried to stop the suspect

The suspect in the Arizona shooting was apparently at a similar meet-and-greet event with Ms. Giffords in 2007, the sheriff said Sunday. “There was some correspondence between Giffords’s office and him about a similar event and he was invited to attend,” Sheriff Dupnik said. He said he did not know anything more about the 2007 event or why Loughner would have been invited to it.

The sheriff’s office said on Sunday that a search for a possible second suspect person had ended. A man seen in a security video shortly before the suspect shooter went on his spree had been found and interviewed and cleared of any involvement in the shootings.

Investigators said that the man was a taxi driver who drove the suspected gunman to the scene. Upon arriving there, the passenger said he did not have change, and he and the taxi driver went into the supermarket for change and the two then walked out together and separated.

While the authorities have not asserted any specific political motivation to the shootings other than to say that Ms. Giffords was clearly the intended target, the political reverberations continued to be felt across the nation and in Washington, where flags over the Capitol were flown at half-staff in memory of Mr. Zimmerman, the slain congressional staff member.

The new House speaker, John A. Boehner of Ohio, who ordered the flags lowered, decried the attack in an early Sunday appearance in his hometown of West Chester, and said it was a reminder that public service “comes with a risk.” Mr. Boehner urged prayers for Ms. Giffords and the other victims and also told his House colleagues to persevere in fulfilling their oath of office.

“This inhuman act should not and will not deter us,” he said. “No act, no matter how heinous, must be allowed to stop us.”

He also said the normal business of the House for the coming week had been postponed “so that we can take necessary action regarding yesterday’s events.” That business had included a vote to repeal the health care overhaul.

And lawmakers in both parties began a difficult process of soul-searching about the tone of political discourse, as they wondered aloud if a lack of civility might somehow have contributed to the bloodshed in Arizona.

In a roundtable discussion with colleagues on NBC’s “Meet the Press,” Representative Debbie Wasserman Schultz, a friend of Ms. Giffords, said that Americans both inside and outside of government had a responsibility to temper the political discourse.

“It’s a moment for both parties in Congress together,” Ms. Wasserman Schultz said. “We absolutely have to realize that we’re all in this for the same reason, to make America a better place.” She noted that House Democrats and Republicans would soon hold separate “retreats” and urged that the parties also meet together.

“I hope that the Democratic and Republican leadership will make a decision for us to have some kind of not-just-token unity event,” she said. “We should have an event where we spend some time together talking about how we can work better together and then we can move forward together and try to avoid tragedies like this.” Mr. Loughner, who was in custody of the Federal Bureau of Investigation on Saturday night, refused to cooperate with investigators and had invoked his Fifth Amendment rights, the sheriff’s office said.

Mr. Loughner had exhibited increasingly strange behavior in recent months, including ominous Internet postings — at least one showing a gun — and a series of videos in which he made disjointed statements on topics like the gold standard and mind control.

Pima Community College said he had been suspended for conduct violations and withdrew in October after five instances of classroom or library disruptions that involved the campus police.

As the investigation intensified on Sunday, police were still at the scene of the shooting, a shopping center known at La Toscana Village. Investigators have described the evidence collection as a painstaking task given the large number of bullets fired and victims hit.

Mark Kimble, an aide to Ms. Giffords, said the shooting occurred about 10 a.m. in a small area between an American flag and an Arizona flag. He said that he went into the store for coffee, and that as he came out the gunman started firing.

Ms. Giffords had been talking to a couple about Medicare and reimbursements, and Judge Roll had just walked up to her and shouted “Hi,” when the gunman, wearing sunglasses and perhaps a hood of some sort, approached and shot the judge, Mr. Kimble said. “Everyone hit the ground,” he said. “It was so shocking.”

Ms. Giffords, who represents the Eighth District, in the southeastern corner of Arizona, has been an outspoken critic of the state’s tough immigration law, which is focused on identifying, prosecuting and deporting illegal immigrants, and she had come under criticism for her vote in favor of the health care law.

Friends said she had received threats over the years. Judge Roll had been involved in immigration cases and had received death threats.

The police said Ms. Giffords’s district office was evacuated late Saturday after a suspicious package was found. Officers later cleared the scene.

Ms. Giffords, widely known as Gabby, had been speaking to constituents in a store alcove under a large white banner bearing her name when a man surged forward and began firing. He tried to escape but was tackled by a bystander and taken into custody by the police. The event, called “Congress on Your Corner,” was outside a Safeway supermarket northwest of Tucson and was the first opportunity for constituents to meet with Ms. Giffords since she was sworn in for a third term on Wednesday.

As a Democrat, Ms. Giffords is something of anomaly in Arizona and in her district, which has traditionally tilted Republican. Last year, she barely squeaked to victory over a Republican challenger, Jesse Kelly. But she had clearly heard the message that constituents were dissatisfied with Democratic leaders in Washington.

Rabbi Stephanie Aaron, who in 2007 officiated at the wedding of Ms. Giffords and the astronaut Mr. Kelly, and leads Congregation Chaverim in Tucson, said the congresswoman had never expressed any concern about her safety. “No fear. I’ve only seen the bravest possible, most intelligent young congresswoman,” Rabbi Aaron said. “I feel like this is really one of those proverbial — seemingly something coming out of nowhere.”