A former roommate of a key prosecution witness in the Air India trial has become the latest in a number of defence witnesses to suffer memory lapses.

Balbir Singh Gharala, who is testifying on behalf of accused terrorist Ajaib Singh Bagri, took the witness stand on Monday for a second time and contradicted testimony he gave last week.

Gharala told the court he didn't remember testifying that he lied to immigration officials when he got his U.S. citizenship in 1994.

Ajaib Singh Bagri
Ajaib Singh Bagri

Prosecutor Richard Cairns read his statements from court transcripts and asked: "Do you remember that?"

"No," Gharala said.

"This was just a week ago," Cairns said.

Gharala said he must have misunderstood the question.

As an illegal immigrant in New York in 1984, Gharala shared an apartment with five other Sikh men in their 20s, including an FBI informant who by court order can only be identified as John.

John testified earlier that a grinning Bagri told him "we did this" a few weeks after the June 23, 1985, bombings that killed 331 people. He said the meeting took place outside a New Jersey gas station, where he had driven in Gharala's car.

Gharala testified last week, and repeated again Monday, that he never never lent out his car.

He said he didn't remember telling Cairns during an interview earlier this month that he'd lent the car to his former roommate.

While John has testified that he told his roommates about Bagri's confession when he returned home after their meeting, Gharala said last week that he'd never heard of Bagri or a confession.

He told the court Monday that it's possible conversations could have gone on in the apartment without him taking part.

Earlier this month, court proceedings were temporarily halted after Cairns, frustrated with a New York cab driver who said he couldn't remember parts of an interview with the prosecutor, asked the man: "Sir, are you an idiot?"

Bagri, a sawmill worker from Kamloops, and Vancouver millionaire Ripudaman Singh Malik are being tried on eight charges in connection with the bombings, including conspiracy and murder.

Bagri's defence team will introduce what's expected to be their final witness on Tuesday.