Capitol Gunman's Deadly Journey

By the time Russell Eugene Weston began his rampage, investigators now believe, he had gone sleepless for nearly 40 hours and was undergoing a full-blown psychotic meltdown.

Family members have helped agents pinpoint the precise hour it all began, at 8 p.m. CT last Thursday when his father ordered him from the house after Weston killed the family cats.

Food and gas receipts in his truck indicate he drove nonstop
through the night directly to Washington, arriving precisely at 9:15 a.m. ET Friday just outside the city.

There, agents say, Weston encountered a severe traffic accident. He was so angered by the delay he circled the wreckage three times, waving his fist out the truck window and screaming obscenties. A fireman at the scene remembered him distinctly.

Two hours later, Weston was observed in Lafayette Park across from the White House. Agents speculate that if his plan was to attack the president's home, he may have been put off by all the security there.

In any event, he is believed to have driven up Pennsylvania
Avenue, where by 3 p.m. he had parked his truck here and then walked up to Capitol Hill to mingle with tourists.

Sources say he actually entered the capitol twice. The first visit was without his gun to check out the security. By 3:30 he returned to his truck where he loaded a .38 revolver with six rounds, stuffed 20 more bullets into his pocket,and then returned to begin the carnage.

Investigators say they have videotapes of what happened next. The tapes show one of the officers being shot, and another officer returning fire.

And - in a surprise to some lawmen - they show Weston cooly flipping his gun from one hand to the other as he ran down the hallways. With either hand, agents say, Weston was a deadly shot.

More from CBS News