A Montreal woman who was aboard the Detroit-bound flight where a passenger tried to ignite an explosive device says she feared for her life.

Shama Chopra, photographed at home in Montreal on Saturday, says she noticed the man accused of trying to bring down Northwest Airlines Flight 253 while she was boarding the plane in Amsterdam because he appeared nervous. (Peter McCabe/Canadian Press)

Shama Chopra was just four rows ahead of the man accused of trying to blow up the Northwest Airlines passenger jet on Friday when she heard what she thought were gunshots.

"All of the flight attendants started screaming 'fire, fire fire.' Then everybody started coming out of from their chairs and they opened their seatbelts. I could see the flame. It was almost touching the ceiling."

Chopra, 54, said there was enough smoke to make passengers cough.

She said three men leaped out of their seats to restrain the man and put out the fire, using water bottles and their bare hands.

When the fire was extinguished, a flight attendant gave them a rope and the four of them tied up the suspect, now identified as 23-year-old Umar Farouk Abdul Mutallab.

By that time, the plane was just minutes from landing. Chopra, who had been visiting family in India, said she was shaken by the incident but not injured.

While boarding Northwest Airlines Flight 253 in Amsterdam, the Montrealer noticed a man lagging behind, hands on his forehead, lost in thought.

She didn't know the nervous man would be involved in the attempted attack on the flight.

Now home in Montreal, Chopra said she gets scared when she thinks about the incident.

"Somehow this device didn't explode," she said. "If it had exploded, we would be all gone. Finished, 278 people plus the crew."

Melinda Dennis, another passenger, who was seated in the front row of the plane, said the man involved was brought to the front row and seated near her. His legs appeared to be badly burned and his pants were cut off, she said. He was taken off the plane handcuffed to a stretcher, she said.

Investigators are trying to determine whether the suspect was acting on orders from an extremist group such as al-Qaeda.

Intelligence and anti-terrorism officials in Yemen said they were investigating claims by the suspect that he picked up the explosive device and instructions on how to use it in that country.

In Nigeria, the suspect's father told The Associated Press that his son, a former university student in London, had left Britain to travel abroad and might have gone to Yemen, where al-Qaeda has increasingly found safe havens.

With files from The Canadian Press and The Associated Press