Children who survived the shooting spree say the two dead killers, both of whom wore ski masks and trenchcoats, were members of a close-knit group of "loners" known as the "trenchcoat mafia".

This group - which had an entry in the school's 1998 yearbook - is variously described as being obsessed with guns, Nazis, the military, the Internet, rock singer Marilyn Manson and goth-rock culture.

The killers are said to have targeted the school's "jocks" - male athletes.

School dedication

Eric Harris: Described as smart

The two suspects, Eric Harris and Dylan Klebold, are not included in a photograph of the Trenchcoat Mafia in the school's 1998 yearbook.

Listing 13 names next to a smiling group photograph, the entry is typical of teenage exuberance. "Who says we are different? Insanity's healthy!" it reads.

"Remember rocking parties at Kristen's, foosball (table football) at Joe's and fencing at Christopher's! Stay alive, stay different, stay crazy."

Initial reports from education authorities say that the group had never been brought to their attention.

Students tell a different tale.

Violence: Alleged websites link group to violence

Andrew Beard alleged that Harris and Klebold had spoken of "hating jocks" while Sean Kelly, 16, said Harris and several members of the Trenchcoat group had made a video about guns, made racist comments towards black or Hispanic students and bragged about acquiring guns. Another student said they were "really dark people".

Other allegations point towards a sinister circle of teenagers who flirted with the edges of the US's extreme right-wing.

They were said to wear confederate flags on their clothes, a symbol claimed by white supremacists.

Other reports say that they celebrated Adolf Hitler's birthday - the day of the shootings - and would speak German to each other.

Web rumours

While the reports of a well-organised gang have not been verified, rumours have exploded on the Internet.

Within hours, bulletin boards and chat rooms included links to Websites alleged to be associated with the group.

One web page uses the name "Reb" - a nickname said to have been used by one of the gang.

Dylan Klebold: Second suspect

That Website includes a rambling poem including the verse: "I AM YOUR APOCALYPSE/ I AM YOUR BELIEF UNWROUGHT MONOLITHIC JUGGERNAUT/ I'M THE ILLEGITIMATE SON OF GOD".

An America Online user profile said to belong to Eric Harris is reported to have contained the words: "Quit whining, it's just a flesh wound. Kill 'Em AAALLL."

Site adminsitrators are believed to have now erased the Harris page.

Another message posted on AOL claiming to be from the group said: "Trench Coat Mafia in da House', preparin' for the big April 20!!''

Many of these messages are considered fake: A search on the words Trenchcoat Mafia showed more and more entries for the group as the hours passed following the killings.

Another twist to the Website theory has revealed that there are a plethora of related sites using the word "trenchcoat" - all of which appear dedicated to a teenage horror-subculture.

These sites, organised in a webring, focus on fantasy-based gothic horror - one includes poems speaking of a "vat of bitterness", another speaks of a "shadow realm".

While this "dark poetry" may be disturbing, one Website is already carrying a disclaimer denying any link with the killings.

Expressing sympathy to the victims' families, the notice reads: "Yes I have problems. But instead of acting out violently, I write."

Inadequacy

What the Websites may have in common with the killers is a strong sense of teenage inadequacy - and the ability, or lack of, to cope with it.

Poetry: Another alleged website including 'Trenchcoat poetry'

One student who escaped alive said of one of the killers: "He put the gun right in my face and started laughing and said it was because people were mean to him last year.''

Another student, Joshua Lapp, said: "They were known as the Trenchcoat Mafia at our school and they got ridiculed a little bit.

"Everywhere, anywhere, any day, no matter how hot it was they wore a black trench coat."

There had been tensions between the group and the school's athletes.

"When they first walked in they said if there are any jocks in here, they're dead," he said.

Other students spoke of the group being obsessed with violent fantasies including images of decapitation and cracking sick jokes at the expense of other students.

"I knew they were capable of violence, but I just didn't know they would do it," said former group member Pauline Colby.

"They were angry about people not accepting them and no one knowing how smart they were."

Contradictions

But Mark Heckler, father of group member Zach Heckler, said the group considered themselves outside of the norm, but there was nothing sinister in the coats.

"We know these kids," said Mr Heckler said. "Nothing indicated that Harris or Klebold were about to explode."

Neighbours of the Harris and Klebold households said the two were quiet teenagers, adding that Dylan Klebold was a talented student.

While rumours continue to fly, few members of the Trenchcoat Mafia have spoken to the media.

But one who has spoken, Thaddeus Boles, has tried to make it clear that whatever Harris and Klebold did, the rest of the group were no different to their schoolmates who had suffered so much.