Mohammad Momin Khawaja remains locked up in maximum-security detention at Ottawa's Regional Detention Centre, as he has for more than a year, denied bail as he stands accused of conspiring in a plot to blow up British citizens.

On the face of things, that alleged plot bears a remarkable resemblance to the jihadist strike that killed 53 Londoners on the city's transit system last week. And as investigators in London grapple with how four homegrown lads became suicide bombers, they may well see an important case study in the matter of a 26-year-old Canadian and his alleged British and U.S. cohorts.

Allegations of that previous plot remain a major concern in their own right: Sources say U.S. President George W. Bush brought up Mr. Khawaja when he met Prime Minister Paul Martin at a security summit in Texas during the spring.

Presumed innocent while awaiting trial, Mr. Khawaja's life bears some parallels to the bombers who died in last week's carnage, according to broadcast and news reports. He wasn't always regarded as particularly zealous, but a friend of his said in an interview that his personality seemed to change after the Sept. 11, 2001, attacks. Family and friends knew him as a harmless, even shy, young man, but he also allegedly took an interest in playing paintball and firing guns, even using code names for fear of being watched.

He didn't escape attention. Months before he was accused of terrorism, Mr. Khawaja allegedly travelled to Pakistan, where he is said to have become close to an admitted al-Qaeda-linked figure. That 30-year-old man, a Pakistani American named Mohammed Junaid Babar, has pleaded guilty in a New York court to running training camps and procuring ammonium nitrate, an explosive chemical, for al-Qaeda.

"They wanted to, you know, plot or target some targets in the U.K.," Mr. Babar told a judge when he pleaded guilty, without naming names. Now co-operating with police, he said that plot fell apart in "March of '04."

Around that time, as terrorist figures met in Pakistan to fine-tune plans against Britain, Mr. Khawaja allegedly went on to the United Kingdom, where, according to British prosecutors, he met fellow conspirators in an Internet café and talked to them about making bombs. Fears sparked by communications intercepts were made tangible weeks later when Scotland Yard seized a half-tonne of ammonium nitrate from a storage shed.

On that same March day, officers belonging to the RCMP's tactical squad broke down the door of the Khawaja family's two-storey, white-frame home in the Ottawa suburb of Orleans. They briefly detained relatives as they found their suspect at his job: Mr. Khawaja had recently returned from Britain to go back to work fixing computers for Canada's Foreign Affairs Department.

A CBC documentary, and various other reports and interviews, have shed some light on what are alleged to be Mr. Khawaja's activities. A publication ban exists on the preliminary hearing in the Canadian court case.

The RCMP have said they picked up Mr. Khawaja in connection with the arrest of the nine U.K. residents of Pakistani heritage - all of them are accused of making a collective journey into violent jihad, an allegation they deny. It is that alleged plot that has made them subjects of interest to global intelligence agencies studying the London bombings.

Was there any overlap? It's unclear. French and British officials appear to be at odds in public comments over whether one of the suicide bombers - Mohammed Sadique Khan, 30 - was a target of the 2004 roundups, and a French official's assertion that some of the suicide bombers were arrested and got away the previous year has been dismissed as having "absolutely no foundation" by the British Home Secretary. The New York Times has also quoted an anonymous investigator as saying at least one of the suicide bombers may have had telephone contact with one of the men arrested in connection with the 2004 plot.

The Jamaican-born suicide bomber, Jermaine Lindsay, was connected to the suspected 2004 plot, one official told The Wall Street Journal.

The clear common denominator, however, is carnage, or fear of it. Police allege that the first group of suspects had hoped to convert the ammonium nitrate into powerful cellphone-triggered bombs, and explode them inside London nightclubs or train stations. If a half-tonne of the potent explosive material were to have been used to that end, the body count could have been much worse than the subway attacks.

Ottawa lawyer Lawrence Greenspon suggests that his client, Mr. Khawaja, may be the victim of misguided perceptions of Muslims by Canadian security agencies.

"We believe he is innocent," Mahboob Khawaja, the young man's father, said yesterday.

The elder Mr. Khawaja condemned the new attacks as "heartbreaking," but stressed they have nothing to do with the arrest of his son. "We do not see any connection between those incidents in Britain, because my son has been locked up a long, long time before."

Regardless, police on both sides of the Atlantic seem firm in their convictions that last year they nabbed bona fide terrorists who had nearly slipped through cracks as Western society had yet to wake up to the threat of homegrown extremists. Scotland Yard called its undertaking Operation Crevice. The Mounties dubbed their investigation Project Awaken.

In the 1970s, Mr. Khawaja's parents met in Ottawa after separately emigrating from Pakistan. The family moved to Saudi Arabia for a few years after Mahboob Khawaja landed a teaching job. An outspoken scholar, the father has written several essays denouncing "American-Zionist collaborative political encroachment in the Middle East" as well as secular Muslim leaders he accuses of kowtowing to Western governments.

Still, by several accounts, Momin Khawaja watched in horror from Canada as hijacked airliners razed the World Trade Center towers in New York. "He said he just felt sorry for all the innocent people who died," his brother said last year. But the attack and the subsequent invasion of Afghanistan prompted a lot of curiosity: Who was this Osama bin Laden? Why was he doing what he did?

"We said, 'How can a Muslim guy use Islam to kill all the innocent people?' " one of Mr. Khawaja's friends, Younes Lasfar, told the CBC's fifth estate in a documentary this year. "We couldn't understand this and then we heard about those tapes on the Net and the books that talk about this ideology of the people.

"We're like, you know, we should check it out and know what this is all about."

Even before that, Mr. Khawaja was allegedly becoming more devout, growing a beard, praying daily and working out more frequently. Friends say he could bench press up to 300 pounds.

He was studying computers at Algonquin College, but in his spare time, according to his friends, he began playing paintball with some friends. Given the Sept. 11 backlash, they thought it prudent to do this somewhat surreptitiously: When making plans on the phone, they said they were about to play "hockey" and gave themselves Western names like Robert and Matthew when they talked about doing this.

"You never know who is listening in and reading our e-mails," Mr. Lasfar told the CBC. "So maybe they might not hear about it and we'll just play in peace."

At this time, Mr. Khawaja was also allegedly stepping up his Internet activities, reportedly logging on to chat rooms and running a blog.

The Canadian Security Intelligence Service declassified some reports this year in which the spy service expressed fear about young Muslim extremists playing paintball and logging on to the Internet. "Canadian jihadists are also very computer literate," one report said. It added, "the young extremists also have access to a greater international on-line network than is available in the developing world."

In 2003, Mr. Khawaja went to Pakistan, telling friends he was off in search of a bride. He had courted an Pakistani American on the Internet. But there was another figure Mr. Khawaja allegedly saw in Islamabad - Mohammed Junaid Babar, whom he brought to dinner at the house of his bride-to-be, she said in an interview with the CBC.

A naturalized American from Queens, Mr. Babar arrived in Pakistan after leaving a $70,000-a-year computer job in New York - his mother reportedly had to flee down the stairs of the World Trade Center during the 2001 attacks. Yet, his sympathies were with al-Qaeda.

"My loyalty has always been, is and forever will be, with the Muslims," he told a Canadian camera crew that caught up with him in Pakistan in 2001. "I can't stand by and live in America while my Muslims are being bombed in Afghanistan."

He ended up running a training camp in the lawless tribal region of Waziristan, Pakistan. Arabs who had aligned themselves with the Taliban fled there after U.S. forces ousted the regime.

In early 2004, al-Qaeda figures are believed to have had a terrorism summit in Waziristan. If there were any intersection between the British plots, this is likely where it happened.

"Intelligence is being re-examined from the terror summit. It was a gathering of terrorism's new generation," the Asia-Pacific Foundation, a U.K.-based security think tank, wrote in a paper circulated yesterday.

It and other sources have suggested that police believe an as-yet-unidentified "British-born mastermind" of the subway attacks knew a senior al-Qaeda figure who took part in an al-Qaeda terror summit.

Another of the alleged attendees was Adnan Shukrijumah, a fugitive al-Qaeda organizer whom the United States fears may be travelling on a false Canadian passport.

There were others.

"From Queens in New York city came Mohammed Junaid Babar, a Pakistani American who arrived with cash, sleeping bags, other supplies for the mountain-bound jihadis," writes the Asia-Pacific Foundation.

The American's Canadian friend was no longer in Pakistan at that point, however, having moved on to England. The spring of 2004 would be a turning point for both.

Western security agencies had picked up telephone conversations and e-mail traffic that made them fearful of an attack on Britain. Mr. Khawaja was watched as he arrived in London.

British prosecutors now say he was spotted talking to other local men at an Internet café in London. The finer points of using cellphones to explode bombs - a technology used in the recent Madrid attacks - was allegedly discussed, according to the Crown.

No arrests were made at the Internet café. They came weeks later. And not long after the Mounties battered down the door of the Khawaja family home, authorities in New York scooped up Mr. Babar.

"The Joint Terrorist Task Force has had that guy on their radar screen since that interview, so they were looking to pick him up when he returned to the United States," an unnamed official told The New York Times last year.

Documents show that Mr. Babar has since pleaded guilty to several counts of lending material support to al-Qaeda. Facing up to 30 years in jail, he has agreed to co-operate with investigators and inform on the people he knew.

It is possible that U.K. investigators have taken a renewed interest in him after the subway attacks. And it's also possible that he may eventually surface as a witness when Mr. Khawaja goes on trial - which may take place next year.

"I was aware that some of the people who attended the jihad training camp had ideas about, you know, plotting against some targets in the United Kingdom and I provide some of the materials I . . . knew where it was going to, what it was going to be used for eventually."

With a report from Jane Taber

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