Nina Jibran had everything to live for. The Lebanese school teacher was recently married, pregnant and living in a comfortable compound in Riyadh.

There was even talk of her moving to Canada with her husband, an engineer who worked for a multinational advertising agency.

But then, shortly after the couple returned home from an obstetrician's appointment last Saturday, a suicide bomber ripped through the gates of their residential area, shredding their lives and sparking outrage in Saudi Arabia. Ms. Jibran was among the 17 dead, and her husband, Eliyas, among the more than 120 injured.

"Nina told me that she was happy in Riyadh and was preparing to leave for Canada as soon as she got her papers," relative Ezabel Matta told the London-based Arabic-language newspaper Asharq al-Awsat.

As details emerge about the victims of last weekend's bombing, many observers believe their profile made them targets for the suspected al-Qaeda attack. Ms. Jibran, like her husband whom she married in July of 2002, was Christian. According to Arabic-language news reports, they had also received documentation to move to Canada.

Elias Bijjani, a Toronto-based member of the Lebanese Canadian Coordinating Council, said many of the couple's neighbours were also Lebanese Christians. He speculated al-Qaeda was targeting Christian Arabs, rather than Muslims.

A senior Saudi official said that investigators had arrested an unspecified number of people in connection with the case, but that some had already been released.

Also yesterday, the Arabic weekly Al-Majalla, published in London, said it had received an e-mail message from an operative of al-Qaeda identified as Abu Mohammad al-Ablaj, taking responsibility for the bombing. Saudi and U.S. officials had already blamed al-Qaeda.

The threat of another attack remains high, a senior U.S. diplomat told The New York Times.

"Whether they have done their deed and are now planning for something else we really can't say," said Gary Grappo, the deputy chief of the U.S. mission. "If you look at al-Qaeda's M.O., there is a pattern in terms of simultaneous or sequential attacks, so our caution to American citizens here is that they need to remain vigilant and cautious in terms of their daily lives."

Najim Tabcharani of Toronto, speaking from his hospital bed, told The Canadian Press he was lucky to be alive. The 55-year-old, who was in his house during the attack, said he heard what he thought was gunfire and a series of explosions. Dust and debris obscured the view from his kitchen window.

"It was exactly like a hell," he said. The electronics engineer, who has worked in Saudi Arabia for 20 years, is recovering after about six hours of surgery to repair neck injuries caused by flying glass.

Sasha, 17, a student from Montreal, received stitches on his forehead in hospital and was released.