The only person convicted in connection with the 1985 Air India bombing, will not get out of prison before his sentence ends next year, Canada's National Parol Board said on Tuesday.
The board upheld an earlier decision denying Inderjit Singh Reyat parole, meaning he will remain behind bars until the end of his five-year sentence in February 2008, a spokeswoman said.
Reyat pleaded guilty in 2003 to a charge of manslaughter for helping collect materials used to make bombs, and was later called as a witness on the murder trial of Ripudaman Singh Malik and Ajaib Singh Bagri.
Reyat, who is awaiting trial on a perjury charge, testified in Malik's and Bagri's trial that he knew nothing of the conspiracy that led to the bombing of Air India Flight 182 that killed 329 people over the Atlantic in June 1985.
Malik and Bagri were both found not guilty.
Reyat, a Duncan, British Columbia, electrician who also holds British citizenship, had earlier been convicted of manslaughter for helping construct a bomb intended for another Air India flight over the Pacific Ocean.
That bomb was intended to go off at the same time as the Flight 182 blast but instead exploded prematurely and killed two Japanese airport workers, according to police.
Both bombings are believed to have been the work of Sikh militants based in Canada who wanted revenge on the Indian government for its 1984 storming of Sikhism's Golden Temple.
Canada is holding an official inquiry into how it might have prevented the Air India bombings, and whether the police investigation was bungled, allowing the bombers to not get caught.
The attack on Flight 182 remains history's deadliest bombing of an airliner.