One of the Washington sniper suspects gave police the vital clue that led to their arrests because he was angry at not being taken seriously.

One of the suspects, 17-year-old John Lee Malvo allegedly called an FBI hotline in Maryland on 17 October.

He was said to be in a rage that the snipers were not being taken seriously and told the operator to ''check out the murder-robbery in Montgomery if you don't believe me''.

Investigators initially believed this was a reference to Montgomery, Maryland, but switched their attention to a fatal robbery that took place in Montgomery, Alabama.

Fingerprints

According to the New York Times, this was after the sniper had made two more calls - to priests in Ashland, Virginia and Bellingham, Washington - specifying that he meant the city in Alabama.

A composite of the Alabama robber, said to resemble John Lee Malvo

A woman was shot dead and another injured during a robbery outside a liquor store in Montgomery, Alabama, on 21 September.

Following that incident, Alabama police constructed a composite picture of one of the suspects and found a fingerprint - reportedly on a magazine about firearms.

When investigators from the sniper taskforce contacted Alabama police, the fingerprint was checked with files of the FBI and the Immigration and Naturalisation Service.

They were confirmed to be those of Mr Malvo.

The composite drawn from the recollection of a police office who chased the Alabama robber also showed a ''very good similarity'' to Mr Malvo, Alabama police said.

Chevrolet link

Soon after, detectives linked Mr Malvo to the Gulf War veteran John Allen Muhammad, 41.

A man inspects the site of the uprooted tree-trunk in Tacoma, Washington

This in turn led police to a housing complex in Tacoma, Washington, where Mr Malvo and Mr Muhammad had been living up to about three months ago.

By Tuesday, police had also linked Mr Muhammad to a blue 1990 Chevrolet Caprice registered in his name in New Jersey.

Late on Wednesday, Maryland police gave Mr Muhammad's and Mr Malvo's identities and the car's description to the media.

Within an hour, the car was spotted by a truck driver near Middletown, Maryland.

Police kept the car under surveillance for two hours before moving in and arresting the pair without a struggle.

Meanwhile, detectives descended on the Tacoma complex and took away evidence including a tree-trunk said to have been used for target practice.

A search of the suspects' Chevrolet turned up a Bushmaster AR-15 rifle.

The federal Bureau of Alcohol, Firearms and Tobacco later said the rifle had been linked by ballistics to 11 of the 14 Washington-area shootings.