Eyewitness accounts and closed-circuit television footage of the moments before an explosion ripped through the JW Marriott hotel in Jakarta on Friday have raised fears the suicide bomber may have been purposefully targeting a meeting of largely Western businessmen.

The nearly simultaneous suicide attacks on the JW Marriott and Ritz Carlton have killed nine people and injured 53 others. Police suspect the involvement of Jemaah Islamiyah, an al Qaeda-affiliated local terrorist organization blamed for a number of attacks in Indonesia between 2000 and 2005 that killed almost 300 people.

Noke Kiroyan, an Indonesian citizen and former local chairman at mining company Rio Tinto PLC (RTP), was one of 19 executives breakfasting in a small lounge in the JW Marriott, which the group hires each Friday for its meetings.

Kiroyan, who lost part of his right ear in the attack, said he believes the bomber would have chosen the main restaurant on the other side of the JW Marriott's lobby, where most guests were breakfasting and which was the target of a 2003 attack on the same hotel, if he had wanted to inflict the maximum number of casualties. "I think we were targeted," he said.

Other Western executives in Jakarta said concerns over the possible targeting of top business elites may lead foreign businesses to be more cautious about how they operate here and possibly recalibrate expansion plans. In recent years, Indonesia has made strides in arresting terrorists, making Westerners feel more secure. ExxonMobil Corp. (XOM) and other foreign resource companies had recently planned to increase the number of expatriate staff in Indonesia.

Police said suspects in Friday's attacks had checked in to room 1808 of the JW Marriott two days before, using it as a command center. In the room, the suspects had assembled bombs, which they had smuggled into the hotel disguised as laptops, police said.

Just before the blast, early Friday morning, the hotel's closed-circuit television caught images of the suicide bomber, wearing a backpack on his chest and wheeling a suitcase, turning left in the lobby and walking purposefully toward the lounge.

The bomber was challenged by a hotel security guard as he approached the room but was waved through after saying he was delivering a package to his boss. Moments later, while at the entrance of the lounge, which was cordoned off with rope, he detonated his bomb, which police said was packed with nails.

Kiroyan, who was sitting at a conference table with his back to the lounge's entrance and was partly shielded by a pillar, said he was sitting next to Jim Castle, a longtime U.S. expatriate and business consultant in Jakarta, who organizes the weekly meetings.

The last thing Kiroyan remembers before the blast is reading a long message from his wife on his mobile phone. "Suddenly there was a loud bang and a blinding flash," he said. "My first thought was that my mobile phone exploded. You hear stories about mobile phones exploding. But then I realized it couldn't be that."

Suddenly, Kiroyan was lying on the floor in pitch darkness with his clothes soaking wet. What he at first took to be blood turned out to be water from the hotel's emergency sprinkler system. People were crying out that they couldn't see. One Indonesian man, an executive with Freeport-McMoRan Copper & Gold Inc. (FCX) was said to have shouted "Allahu Akbar" or "God is great" in Arabic.

Kiroyan then made his way out of the room, where he was met by two hotel staff and guided outside to wait for an ambulance. "I feel angry but relieved that I am alive," Kiroyan said.

Although he did not directly observe the suicide bomber, Kiroyan said other colleagues at the meeting later recounted that some of the people in the room remember seeing an unknown Indonesian man at the entrance just before the explosion.

Castle, whose consultancy CastleAsia organized the event, called the incident a "tragedy." He said in an email that four people, including himself, avoided serious injury because of a pillar and the angle of the room.

The four foreigners who have so far died in the Marriott explosion - three Australians and a New Zealander - were all sitting at the far end of table from Kiroyan and Castle, nearest the entrance. An Indonesian waiter and the suicide bomber were also killed in the explosion.

Indonesian terrorists have failed in recent years to kill a large number of Westerners in suicide bombings.

In 2002, the Bali nightclub attacks killed 202 mainly Western tourists through two bombs, one in a car and the other carried in a backpack by a suicide bomber. But since then Indonesian police have arrested scores of Islamic terrorists, diminishing Jemaah Islamiyah's capacity to hit a large number of Westerners.

An earlier attack on the JW Marriott in Jakarta in 2003, by a car bomb, killed 12 people, two-thirds of them Indonesians, and injured more than a hundred. Other bombings against Western targets in Jakarta in recent years also have killed more Indonesians than foreigners, including a 2004 truck bombing on the Australian embassy that failed to kill a single diplomat but maimed Indonesian security guards and passers-by.

An attack on Bali seafood restaurants in 2005, the last major incident on Indonesian soil before Friday's bombings, killed mainly Indonesians.

Foreign expatriates living in Jakarta said none of the previous attacks so directly targeted foreign business interests. The idea that the meeting Friday may have been a focus was "a scary thought" said William Reed Rising, a U.S. citizen who works in real estate and normally attends the briefing but was absent last week.

-By Tom Wright, The Wall Street Journal; tom.wright@wsj.com