A security supervisor ignored the repeated beeping of a bomb-detecting scanner when it was passed over a large suitcase at Toronto airport during the security check for the Air India Kanishka flight that exploded off the Irish coast in 1985 killing all 329 passengers on board.

Antonio Coutinho, a station attendant for Air Canada in 1985, told the British Columbia Supreme Court on Wednesday that the hand-held security wand beeped repeatedly when passed over a heavy 70-kilogram suitcase checked in at the Toronto Pearson International Airport in Canada.

He was testifying at the trial of Vancouver businessman Ripudaman Singh Malik and Kamloops millworker Ajaib Singh Bagri who have accused of masterminding the bombing of the ill-fated flight and charged with murder of 329 passengers.

The bag made it to the Air India Flight 182 after a security supervisor decided a lock on the suitcase had triggered the alarm, Coutinho said.

"There were lots of bags with zippers and with locks, but they never beeped; only this one particular bag. The beep sound came in the centre of the bag and then on the left side. I seen all the bags that came through with locks and I never heard the sound," Coutinho told the B C court.

He said the beeping suitcase in Toronto had a reddish-brown tag and was destined for Mumbai and was loaded in the bulk load at the rear of the Air India flight 182, the court was told.

The Vancouver court is trying to connect pieces of what is believed to be the most complex criminal case in Canadian history.

The Kanishka bombing: Complete Coverage