Revealed: gunman's weird countdown to Tucson rampage

Investigators piece together bizarre behaviour in hours leading up to attack on congresswoman

Bizarre details of the hours that a disturbed young American spent in his hometown before he shot the congresswoman Gabrielle Giffords, wounding her severely and killing six others, have been revealed.

Jared Loughner's descent into violence took place on a furious all-night excursion through the dark streets of Tucson, meandering from one store to another as he prepared to take revenge on a world from which he had become increasingly alienated. He checked into a down-and-out motel. He picked up photos showing him holding a Glock 19 handgun while wearing only a bright red G-string. He bought ammunition on one of three trips to two different Walmarts.

He called a high-school marijuana-smoking buddy, ran away from his father into a cactus-dotted desert, and updated his MySpace profile to say "Goodbye friends".

Michelle Martinez ran into Loughner during his rambling odyssey. She and some friends were in the neighbourhood when a sullen figure emerged from the darkness and startled them. Loughner picked his way through the group rather than walk around them, offering a deep, distant: "What's up?" He then quickened his pace and disappeared into the darkness. "I had a feeling he was thinking about something," said Ms Martinez, who knew Loughner from their school days. "It was just kind of weird."

The encounter epitomises the hours that Loughner spent as he became increasingly unhinged. The chaotic night began at 11.35pm when he dropped off a roll of 35mm film at a Walgreens drug store. In the next hour he stopped at a Circle K petrol station and convenience store and checked into a Motel 6, a £24-a-night spot popular with truckers and close to a Long John Silver's and other fast-food restaurants.

If he slept at all that night, it wasn't for long. At 1.45am, he was back outside his parents' home, where he ran into Ms Martinez and her friends. At about 2am, he called an old friend, Bryce Tierney, got no reply and then headed back to the Walgreens, where – at 2.19am – he picked up the developed photos. And 15 minutes later, he stopped to make more purchases at yet another convenience store. At 4.12am Loughner was at a computer keyboard in an unknown location, typing a farewell bulletin on his MySpace page. Authorities said the photo included in that posting was from those that he had picked up at Walgreens hours earlier.

After one additional stop, Loughner began his quest for ammunition. His first stop, a Walmart between his house and the scene of the shooting, doesn't sell bullets before 7am. It was only 6.12am. He returned at 7.04am, but left the store without making a purchase. He then drove five miles west to a Walmart superstore, where he purchased 9mm ammunition and a black, backpack style bag. It was now 7.27am.

Just three minutes later, he was pulled over for driving through a red light in his 1969 dark grey Chevy Nova. Loughner was co-operative, and the officer from the Arizona Game and Fish Department took his licence and vehicle registration information. Loughner had no outstanding warrants and was let go with a warning. And without a search. At around 8am, Loughner returned home and had a confrontation with his father. He then drove off into desert scrub, shook off his father who was in pursuit, and returned to the Circle K he'd visited three hours earlier.

He was carrying two extended pistol clips that hold up to 33 bullets, along with two 15-round magazines, a 4in buck knife, a Visa card, his driving licence and cash in a plastic bag. Authorities said a cab picked him up at 9.41am. His destination was a Safeway store – and a violent confrontation with Gabrielle Giffords.