The long and aimless journey across US that ended in a mindless orgy of murder

It was a classic American journey, aimless, anonymous and headed inexorably towards a final orgy of devastating, meaningless violence. For 14 months, from the time the family life of John Allen Muhammad fell apart until his arrest on Thursday as the Washington-area sniper, he dropped out of society and took to the road, slowly making his way from the Pacific north-west to the east coast.

Most of that time, he was with his fellow suspect, Lee Boyd Malvo, the 17-year-old Jamaican he called his stepson. They were nearly destitute and on the run for petty crimes. Until September, it seems they had no car, no means of support, and nowhere to sleep. What for many is a voyage of discovery became, for them, a descent into hell. Nobody knows, yet, what might have motivated the pair to start the shooting spree, killing 10 people over 22 days.

And nobody knows what they did between the time they left Tacoma, Washington, in February and their arrival in suburban Maryland a few weeks before the attacks began. Mr Muhammad's breakdown appears to have begun in August 2001. He had taken his three children to live in a homeless shelter in Bellingham, north of Seattle. When he applied for state aid, his cover was blown and police took the children back to their mother.

Then Mr Muhammad became close to Mr Malvo, possibly because he was having an affair with his mother, Uma James. But she became so worried she complained to police. Officials found Mrs James and her son were in the country illegally, and held them in custody. That was in December. In February, Mrs James posted bail and got herself and her son out, pending a deportation hearing. Days later, Mr Malvo and Mr Muhammad took off.

They headed to Tacoma, where Mr Muhammad was arrested for shoplifting. He never showed up in court. In late August they were in New Jersey, where Mr Muhammad bought a 12-year-old Chevy Caprice for $250. On 21 September, they were in Montgomery, Alabama, where a liquor store clerk was killed and another wounded in a hold-up. Mr Malvo's fingerprint was found.

Days later, they turned up in Clinton, Maryland, where Mr Muhammad's ex-wife and children now live. Somehow, they got a Bushmaster XM-15 A3 high-velocity rifle. In early October, the sniper attacks began.