Bonded by guns and indifference to human life

John Allen Muhammad and John Lee Malvo, man and boy, seem to have a special bond. Mr Muhammad told people they met that Mr Malvo, a 17-year-old Jamaican, was his stepson, but there are no documents to prove it.

Whatever their legal connection, they clearly shared something far deeper: a fascination with guns and a chilling indifference to human life.

Mr Malvo lived with Mr Muhammad for several years in Washington state, near Fort Lewis army base, where the elder man had been stationed as a soldier in the 1980s. Mr Williams - as Mr Muhhamad then was - was later posted to California, but returned to the area a decade later, after parting ways with the military in unclear but apparently bitter circumstances.

At about the same time he split up with his first wife and converted to Islam, although he did not change his name until last year.

A former friend and business partner in the area, Felix Strozier, said he was "a strong believer in the Muslims", but it was not clear last night whether he joined any Islamic groups.

He worked as a mechanic and invested some money in a martial arts school with Mr Strozier. Although he told his friend he had been in the special forces (he had been a regular soldier and had fought in the Gulf war), he did not practise martial arts. He asked Mr Strozier to teach Mr Malvo and a younger son, "Little John", from his second marriage.

Mr Strozier remembers Mr Malvo as aggressive, even at the age of 13. Of Mr Muhammad he said: "He seemed to be a pretty nice person. He was quiet, but a couple of times I saw him get upset so I knew there was a different side to him."

The two men eventually fell out over money: Mr Muhammad had borrowed $500 (£322) from the martial arts funds accounts and did not repay it.

Mr Muhammad took Mr Malvo to a school in nearby Bellingham county, where, according to the local police, the Jamaican-born boy presented no academic records. The school is reported to have described the boy as a quiet, unremarkable student who kept to himself and spent a lot of time in the library.

The Bellingham police chief, Randy Carroll, said: "He stayed in school briefly. Then we lost contact with him, and he moved on."

Mr Muhammad himself seems to have slipped off the rails during this period. His second wife, Mildred, took out a restraining order against him in February 2000 after they rowed about care of the children, and he tried to force his way into her house.

But a search for a criminal record revealed little.

The Pierce county sheriff's spokesman, Ed Troyer, said Mr Muhammad had been cited for traffic violations and put in the county jail at least once, but all were minor incidents.

He ended up with Mr Malvo in the Lighthouse Mission, a homeless shelter in the Seattle area, but at some point was able to rent the Tacoma house, where the two of them seemed to have taken up shooting at a tree in the garden.

Three months or more ago they set off across the country. They turned up unannounced at the house of Mr Muhammad's first wife, Carol Williams, in Baton Rouge, Louisiana.

Sheron Norman, a former sister-in-law, said they came for a three-day visit. It was the first time a member of the family had seen Mr Malvo, she said, and Mr Muhammad introduced him as his son.

After a few days in Baton Rouge the two went to Maryland, just outside Washington DC, where the saga of their strange bond reached its bloody culmination.