TUCSON — A wildlife officer pulled over the suspect in the assassination attempt against an Arizona congresswoman less than three hours before the deadly attack, authorities said Wednesday as they pieced together more details of a frenzied morning.

Jared Loughner ran a red light but was let off with a warning at 7:30 a.m. Saturday, the Arizona Game and Fish Department said. The officer took Loughner's driver's license and vehicle registration information but found no outstanding warrants on Loughner or his vehicle.

Wildlife officers don't usually make traffic stops unless public safety is at risk, such as running a red light. The stop was on an access road that connects to Interstate 10, well away from the grocery store, said Game and Parks spokesman Jim Paxon.

"He had a valid license, the car was registered, he had insurance," Paxon said. "He was warned and released because we had no probable cause to hold, or do an extensive search."

It's the latest evidence of Loughner's busy morning before police say he showed up at a Tucson grocery store in a taxi at 10:11 a.m. and shot 19 people, killing six, including a federal judge and a 9-year-old girl.

Also that morning, Loughner, 22, ran into the desert from his angry father, who was chasing his son after seeing him remove a black bag from the trunk of a family car, said Rick Kastigar, chief of the department's investigations bureau. Investigators are still searching for the bag.

Hours after the attack, sheriff's deputies swarmed the Loughners' home and removed what they describe as evidence Loughner was targeting Giffords. Among the handwritten notes was one with the words "Die, bitch," which authorities believe was a reference to Giffords.

Investigators with the Pima County Sheriff's Department previously said they found handwritten notes in Loughner's safe reading "I planned ahead," ''My assassination" and "Giffords." Capt. Chris Nanos said all the writings were either in an envelope or on a form letter Giffords' office sent him in 2007 after he signed in at one of her "Congress on Your Corner" events — the same kind of gathering where the massacre occurred.

Meanwhile, the city held a tribute to victims the eve of a presidential visit.

On Tuesday night, several hundred mourners filled a Tucson church for a public Mass to remember the slain and pray for the injured. As people filed in, nine young girls sang "Amazing Grace." The youngest victim of the attack, 9-year-old Christina Taylor Green, was a member of that choir.

"I know she is singing with us tonight," said Tucson Bishop Gerald Kicanas, who presided over the service.

President Barack Obama visits Arizona Wednesday and will honor the victims in a speech to a rattled state and nation.

In one apparent reaction to the shooting, the FBI said background checks for handgun sales jumped in Arizona following the shootings, though the agency cautioned that the number of checks doesn't equate to the number of handguns sold.

Still, there were 263 background checks in Arizona on Monday, up from 164 for the same day a year ago — a 60 percent rise. Nationally, the increase was more modest: from 7,522 last year to 7,906 Monday, a 5 percent jump.

Loughner's parents, silent and holed up in their home since attack, issued a statement Tuesday, expressing remorse over the shooting.

"There are no words that can possibly express how we feel," Randy and Amy Loughner wrote in a statement handed to reporters waiting outside their house. "We wish that there were, so we could make you feel better. We don't understand why this happened.

"We care very deeply about the victims and their families. We are so very sorry for their loss."

Giffords is breathing on her own and responding non-verbally to doctors after being shot in the head.

"We have really decreased the amount of sedation we are giving her and as a result of that, she's becoming more and more spontaneous all the time," said Dr. Peter Rhee, trauma chief at the University of Arizona.

Sheriff's deputies had been to the Loughner home at least once before the attack, spokesman Jason Ogan said. He didn't know why or when the visit occurred, and said department lawyers were reviewing the paperwork and expected to release it Wednesday.

The visits were for nonviolent incidents, including a report by Jared Loughner of identity theft, a noise complaint and Amy Loughner's claim that someone had stolen her license plate sticker, according to a report by The Wall Street Journal.

In addition to the new details about the hours before the shooting, interviews with those who knew Loughner or his family painted a picture of a young loner who tried to fit in.

Before everything fell apart, he went through the motions as many young men do nowadays: Living at home with his parents, working low-wage jobs at big brand stores and volunteering time doing things he liked.

None of it worked. His relationship with his parents was strained. He clashed with co-workers and police. And he couldn't follow the rules at an animal shelter where he spent some time.

Loughner was arrested in October 2008 on a vandalism charge near Tucson after admitting he scrawled the letters "C'' and "X'' on a road sign in a reference to what he said was Christianity. His address listed on the police report was an apartment near his home.

Loughner eventually moved back in with his parents.

Even when Loughner tried to do good, it didn't work out.

A year ago, he volunteered walking dogs at the county animal shelter, said Kim Janes, manager of the Pima Animal Care Center. He liked dogs; neighbors remember him as the kid they would see walking his own.

But at the shelter, staff became concerned: He was allowing dogs to play in an area that was being disinfected after one had contracted a potentially deadly disease, the parvovirus. Loughner wouldn't agree to keep dogs from the restricted area, and was asked to come back when he would. He never returned.

Loughner grew up on an unremarkable Tucson block of low-slung homes with palm trees and cactus gardens out front. Fittingly, it's called Soledad Avenue — Spanish for solitude.

Solitude found Loughner, even when he tried to escape it. He had buddies but always fell out of touch, typically severing the friendship with a text message. Zach Osler was one such friend.

Loughner's father moved into the house as a bachelor, and eventually got married, longtime next-door neighbor George Gayan said. Property records show Randy Loughner has lived there since 1977. Unlike other homes on the block, the Loughners' is obscured by plants. It was assessed in 2010 at $137,842.

Randy Loughner apparently has not worked for years — at least outside his home.

Amy Loughner got a job with the county parks and recreation department just before Jared was born, and since at least 2002 has been the supervisor for Roy P. Drachman Agua Caliente Park on the outskirts of the city. She earns $25.70 an hour, according to Gwyn Hatcher, Pima County's human resources director.

Linda McKinley, 62, has lived down the street from the Loughner family for decades and said the parents could not be nicer — but that she had misgivings about Jared as he got older.

"As a parent, my heart aches for them," she said.

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Associated Press writers Alicia Chang and Gillian Flaccus in Tucson, Jacques Billeaud and Bob Christie in Phoenix, Christy Lemire in Los Angeles and news researcher Julie Reed in Charlotte, N.C., contributed to this report.

TUCSON — Investigators on Tuesday revealed more disturbing details about the events leading up to the assassination attempt against U.S. Rep. Gabrielle Giffords, including a menacing handwritten note in the suspect's home with the words "Die, bitch."

And on the day of the shooting, a mumbling Jared Loughner ran into the desert near his home after his father asked him why he was removing a black bag from the trunk of a family car, sheriff's officials said. Loughner resurfaced later Saturday when authorities say he showed up at a grocery store in a taxi and carried out the rampage that injured 14 people and killed six, including a federal judge and a 9-year-old girl.

Investigators provided the new details to The Associated Press and said they're still searching for the bag. They suspect it could contain clues into Loughner's motives.

"The bag is very important to us," said Capt. Chris Nanos, head of the Pima County Sheriff's Department's criminal investigations division. "What was in that bag and is there any relevance?"

"What if he wrote a note that says, 'Hey, I'm going to go do these things and I know it's wrong but I'm still going to do them,'" Nanos said. "That'd be a pretty good piece of evidence."

Authorities previously said they found handwritten notes in Loughner's safe reading "I planned ahead," ''My assassination" and the name "Giffords." Pima County Chief Rick Kastigar and Nanos told the AP they also found notes with the words "Die, bitch", which they believe referenced Giffords, and "Die, cops."

All the writings were either in an envelope or on an actual form letter Giffords' office sent him in 2007 after he attended one of her political events, Nanos said.

For all of it, Loughner's parents, silent and holed up in their home since the shooting spree, apologized Tuesday.

"There are no words that can possibly express how we feel," Randy and Amy Loughner wrote in a statement handed to reporters waiting outside their house. "We wish that there were, so we could make you feel better. We don't understand why this happened.

"We care very deeply about the victims and their families. We are so very sorry for their loss."

The apparent target of the attack, Giffords, 40, was able to breathe on her own Tuesday at an intensive care unit here, another hopeful sign of her progress, doctors said.

Meanwhile, several hundred mourners filled a Tuscon church for a public Mass to remember the slain and pray for the injured. As people filed in, nine young girls sang "Amazing Grace." The youngest victim of the attack, 9-year-old Christina Taylor Green, was a member of that choir.

Yvonne Ignacio, 53, went to the Mass after learning about the shooting while she was listening to a conservative talk radio Saturday.

"I am dismayed that it's become political. That's disrespectful to the victims and that's why we're here," said Ignacio, who is a tea party member.

On Wednesday, President Barack Obama will visit Arizona and give a speech honoring those killed.

In addition the new details about the hours before the shooting, interviews with those who knew Loughner or his family painted a picture of a young loner who did try to fit in.

Before everything fell apart, he went through the motions as many young men do nowadays: Living at home with his parents, working low-wage jobs at big brand stores and volunteering time doing things he liked.

None of it worked. His relationship with his parents was strained. He clashed with co-workers and police. And he couldn't follow the rules at an animal shelter where he spent some time.

One close high school friend who requested anonymity to avoid the publicity surrounding the case said he would wait outside 10 minutes for Jared to leave the house when they were going out.

When Jared would get into the car, he'd say that it took so long because his parents were hassling him.

The parents of another close friend recalled how Loughner's parents showed up at their doorstep in 2008 looking for their son, who had left home about a week before and broken off contact.

While the friend, Zach Osler, didn't want to talk with the AP, his parents Roxanne and George Osler IV did.

With the Loughners at their house, Zach Osler told them the name of the local hotel where their only child was staying, Zach's father said. Jared moved back in, he said.

After that, Osler's dad sometimes would see Mrs. Loughner at the local supermarket, though they didn't chat much. He recalled that every time he saw her she had at least one 30-pack of beer in her cart.

Loughner, now 22, would come over several times a week from 2007 to 2008, the Oslers said.

The boys listened to the heavy metal band Slipknot and progressive rockers The Mars Volta, studied the form of meditative movement called tai chi, and watched and discussed movies.

Loughner's favorites included little-known conspiracy theory documentaries such as "Zeitgeist" and "Loose Change" as well as bigger studio productions with cult followings and themes of brainwashing, science fiction and altered states of consciousness, including "Donnie Darko" and "A Scanner Darkly."

Even in small talk, he struck the Oslers as unusual.

"He always said, 'Hi, Mrs. Osler. How are you today?' When he left he made a point of coming over and saying, 'Thank you for having me over,'" said Roxanne Osler, noting that was not typical for Zach's friends. "Jared struck me as a young man who craved attention and acceptance."

Once he shared with the Oslers a short story he had written about a reporter meeting an angel during the apocalypse.

George Osler IV read it, thought it was well written, but couldn't identify the point.

"He seemed like he was kind of offended that I didn't get the message," George Osler said.

Meanwhile, the unfailingly polite kid they knew was getting into trouble.

Loughner was arrested in October 2008 on a vandalism charge near Tucson after admitting that he vandalized a road sign with a magic marker, scrawling the letters "C'' and "X'' in a reference to what he said was Christianity.

The case was ultimately dismissed after he paid a $500 fine and completed a diversion program.

Even when Loughner tried to do good, it didn't work out.

A year ago, he volunteered walking adoptable dogs at the county animal shelter, said Kim Janes, manager of the Pima Animal Care Center. He liked dogs; neighbors remember him as the kid they would see walking his own.

At the shelter, staff became concerned: He was allowing dogs to play in an area that was being disinfected after one had contracted a potentially deadly disease, the parvovirus.

"He didn't think the disease was that threatening and when we tried to explain how dangerous some of the diseases are. He didn't get it," Janes said.

He wouldn't agree to keep dogs from the restricted area, and was asked to come back when he would. He never returned.

Loughner also jumped from paid job to job because he couldn't get along with co-workers, according to the close high school friend who requested anonymity. Employers included a Quiznos sandwich shop and Banana Republic, the friend said.

On his application at the animal shelter, he listed customer service work at Eddie Bauer.

Loughner grew up on an unremarkable Tucson block of low-slung homes with palm trees and cactus gardens out front. Fittingly, it's called Soledad Avenue — Spanish for solitude.

Solitude found Loughner, even when he tried to escape it. He had buddies but always fell out of touch, typically severing the friendship with a text message. Zach Osler was one such friend.

Loughner's father moved into the house as a bachelor, and eventually got married, longtime next-door neighbor George Gayan said. Property records show Randy Loughner has lived there since 1977.

Gayan said he and Randy Loughner had "differences of opinion but nothing where it was radical or violent." He declined to provide specifics. "As time went on, they indicated they wanted privacy," Gayan said.

Unlike other homes on the block, the Loughners' is obscured by plants. It was assessed in 2010 at $137,842.

Randy Loughner apparently has not worked for years — at least outside his home. He did fix up cars. Gayan said he had three "show cars" and two of Jared Loughner's friends said he bought a junker 1969 orange Chevrolet Nova and made it pristine.

Amy Loughner got a job with the county parks and recreation department just before Jared was born, and since at least 2002 has been the supervisor for Roy P. Drachman Agua Caliente Park on the outskirts of the city. She earns $25.70 an hour, according to Gwyn Hatcher, Pima County's human resources director.

"She's worked hard, done a good job of keeping it looking good," said Charles Ford, a former Tucson City Council member who is a board member of Friends of Agua Caliente Park.

Linda McKinley, 62, has lived down the street from the Loughner family for decades and said the parents could not be nicer — but that she had misgivings about Jared as he got older.

"As a parent, my heart aches for them," she said.

She added that when she was outside watering her plants she would see Jared riding down the street on his bike, often talking to himself or yelling out randomly to no one.

Once he yelled to some children on the street: "I'm coming to get you!" McKinley said.

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Associated Press writers Alicia Chang and Gillian Flaccus in Tucson, Jacques Billeaud in Phoenix, Christy Lemire in Los Angeles and news researcher Julie Reed in Charlotte, N.C., contributed to this report.