A B.C. Mountie accused of obstruction of justice in a fatal crash has pleaded not guilty, but prosecutors say they plan to present damning evidence that he knew about at hiding evidence of drunk driving.

Cpl. Benjamin "Monty" Robinson was off duty and driving his children home from a Halloween party when he struck Orion Hutchinson's motorcycle with his Jeep at a Tsawwassen intersection on Oct. 25, 2008. Instead of helping the 21-year-old, Crown lawyers alleged that Robinson left the young man to die in the street while he walked home and drank two shots of vodka.

Robinson failed two separate police breathalyzer tests when he returned 10 minutes later, leading Delta police to recommend a charge of impaired driving causing death, but prosecutors said there wasn't enough evidence to support that charge.

Hutchinson's family attended the first day of Robinson's trial in B.C. Supreme Court Monday and sobs could be heard inside the courtroom. Outside the court, mother Judith Hutchinson made an emotional plea for harsh justice.

"Regardless of the outcome, nothing can make our loss less painful. We fervently hope that the outcome of the trial ensures that this individual is not permitted to continue in a position of public trust because, given his track record, we feel that would be an utter and complete travesty," she said.

The woman who hosted the Halloween party on the night of the collision testified Monday that she asked Robinson to pick up some booze and then saw him with a beer at one point, but he never appeared drunk.

Two witnesses to the crash told the court that Robinson approached them after Hutchinson was thrown from his bike and asked them to hold his licence. One remembered him saying, "I've got to get my kids out of here," and "This is gross."

Lawyers for the Crown told the court they plan to present a witness who will testify that they overheard Robinson giving advice on avoiding drunk-driving charges at a Christmas party a year before the crash. The officer allegedly told a group of people that if they ever got into an accident near their home or a bar, the best thing to do is leave their licence at the scene, have a few shots and then return. That way -- there would be no way to tell when the alcohol was in their system.

Another Crown witness is expected to tell the court that Robinson took a breathalyzer course in 2005 and learned about various defences against drunk-driving charges.

The trial is expected to last a week-and-a-half, and it's not known if Robinson will take the stand.

Robinson is currently suspended from the RCMP and is also awaiting trial on a perjury charge related to the death of Robert Dziekanski at Vancouver International Airport in 2007.

Robinson was the senior officer on the scene when the Polish immigrant was stunned several times with a Taser. A special prosecutor who reviewed the case ruled out any charges linked to the four Mounties' conduct on the night of the fatal encounter, but found there was enough evidence to show that the officers deliberately misled investigators about what happened during their confrontation with Dziekanski.

Robinson is scheduled to appear in court on the perjury charge in April 2013.

With reports from CTV British Columbia's Brent Shearer and Maria Weisgarber