A former bank teller who helped her boyfriend and his friends rob a Bank of Montreal (BMO) has been sentenced to 18 months in jail despite asking for a lesser sentence over deportation concerns.

Kenza Belakziz, 24, was escorted out of the courtroom Friday afternoon by sheriffs to begin serving her sentence.

Late last year, Justice David Gates told lawyers he felt their proposal for six months in jail was too low and said the sentence appeared "to be tailored for immigration factors."

Gates said the risk of being deported was "not a good enough reason to deviate from what is otherwise an appropriate sentence."

Belakziz pleaded guilty to conspiracy to commit robbery in October and signed a document confirming she understood the judge was not bound by the sentence proposed by the lawyers.

Originally from Morocco, Belakziz is the only member of her family who never made the effort to become a Canadian citizen. A sentence of more than six months would mean she is likely to be deported to Morocco, where she no longer has family.

When the judge refused to accept the sentence the lawyers had proposed, Belakziz tried to back out of her plea but in March, Gates ruled she would not be allowed.

Gates said a proper sentence for her crime would be two years in jail but took six months off for mitigating circumstances like her mental health concerns and the length of time it's taken for the case to work its way through the system.

The judge will issue written reasons for his sentencing decision at a later date.

Employees held at gunpoint

Belakziz worked at the BMO branch in the southwest community of Mission when she provided confidential information about the bank to her then-boyfriend, Saleem Nasery.

She admitted to giving Nasery information on the layout of the bank, the silent alarm, locations where money was stored and details on bait bills and dye packs.

Police closed down the intersection of Fourth Street and 23rd Avenue in Mission after the bank robbery in November 2014. (CBC)

Nasery and two others then robbed the institution in November 2014, tying up employees and holding them at gunpoint.

By the time the trio of robbers — Nasery, Lucas Windsor and Matthew Valdes — left the bank after 20 minutes with about $12,000 in two bags, police had already set up outside.

Inside job

Initially, investigators believed Belakziz was a victim before they realized it was an inside job. She was charged a month later.

Gates noted the starting point for a conviction of conspiracy to commit robbery is five years in prison, but mitigating factors can bring that down significantly.

Some of the victims — bank employees who had been zip tied together and held hostage — wrote statements describing how the robbery traumatized them and changed their lives forever.

Nasery pleaded guilty in October 2017 to robbery with a firearm, forcible confinement and wearing a disguise. He was sentenced to six years in prison, less time served.

The other robbers, Valdes and Windsor, pleaded guilty in 2015. Valdes received a 5½-year sentence for his role while Windsor got a five-year, two-month prison term.