CBC News has learned the timing of the arrests of the accused in the thwarted Canada Day bomb plot was key, with the suspects heading to a pre-arranged getaway rendezvous just as the bombs were set to go off.

John Nuttall and Amanda Korody were lured to an isolated spot in Abbotsford — on the B.C. mainland, outside of Vancouver — at 2 p.m. PT on Canada Day, where RCMP officers arrested them.

In Victoria, 2 p.m. was to be a highlight of Canada Day celebrations, when people making up a "living flag" would have their photo taken together on the lawn of the B.C. legislature.

Shortly after, at 3 p.m., entertainment would start on the main stage.

Joshua Labove, a terrorism expert at Simon Fraser University, says the RCMP could afford to push a five-month investigation to the eleventh hour because undercover officers had infiltrated the plot — and had made sure the bombs would never explode.

"They want just to be able to show not just that these individuals are conspiring to commit terrorism, but that they're actually willing to go through with it," he said.

Extent of police involvement unclear

But there are other questions about how much undercover officers might have enabled the suspects.

During Tuesday's press conference, when investigators were asked if officers posed as collaborators or supplied materials, the official response was cagey.

- VIDEO: RCMP announces charges and outlines bomb plot

- Bomb plot suspects' behaviour changed 6 months ago, says friend

"The RCMP and its partner agency used all its available resources during this investigation," said assistant RCMP commissioner Wayne Rideout, referring to the Canadian Security Intelligence Service.

Questions have arisen about whether the accused couple were capable of hatching such an elaborate plot, and if they could have built the bombs on their own.

Andre Gerolymatos, another terrorism expert at SFU, says he hopes the RCMP didn't play a "Mr. Big" role in the investigation — something the force has done in the past.

- The Fifth Estate: How Mr. Big stings work

"If the RCMP egged them along, you know, and gave them the rope to hang themselves, that's a long stretch for the police," Gerolymatos said.

Labove agrees, and says the level of police involvement in the investigation will need to be detailed in the coming weeks and months.

"If the RCMP was simply watching these individuals and potentially engaging with them, that's just good investigative work," he said. "But to suggest that they're enabling them and somehow radicalizing them I think is a potentially a more controversial point."

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  • John Nuttall

    John Nuttall is shown in this undated photo. Nuttall, 38, and his partner, Amanda Korody, were arrested on Monday and charged with three counts each in relation to an alleged plot to detonate bombs at the B.C. legislature in Victoria on Canada Day, as thousands celebrated the national holiday.

  • Exterior View Of House

    The exterior of a home that had the basement apartment of alleged terror suspects John Nuttall and Amanda Korody in Surrey, B.C.

  • Front Door Of Basement Suite

    An exterior view of the apartment of alleged terror suspects John Nuttall and Amanda Korody is shown in Surrey, B.C.

  • Bathroom

    The bathroom counter is seen inside the apartment of alleged terror suspects John Nuttall and Amanda Korody in Surrey, B.C.

  • Kitchen

    A man walks through the apartment of alleged terror suspects John Nuttall and Amanda Korody in Surrey, B.C.

  • Kitchen

    Bottles of methadone are seen on the kitchen counter in the apartment of alleged terror suspects John Nuttall and Amanda Korody in Surrey, B.C.

  • Living Room

    The apartment of alleged terror suspects John Nuttall and Amanda Korody is shown in Surrey, B.C.

  • Living Room

    A photogrpaher shoots pictures inside the apartment of alleged terror suspects John Nuttall and Amanda Korody in Surrey, B.C.

  • Bedroom

    Money and a poster are pinned on a wall in the apartment of alleged terror suspects John Nuttall and Amanda Korody in Surrey, B.C.

  • Bedroom

    Inside the apartment of alleged terror suspects John Nuttall and Amanda Korody in Surrey, B.C.

  • Bedroom

    A photographer shoots pictures inside the apartment of alleged terror suspects John Nuttall and Amanda Korody in Surrey, B.C.

  • Bedroom

    Inside the apartment of alleged terror suspects John Nuttall and Amanda Korody in Surrey, B.C.

  • RCMP Chief Supt. Wayne Rideout looks at a photograph of pressure cookers that RCMP say two people intended to use as explosive devices, during a news conference to announce terrorism charges in Surrey, B.C., on Tuesday July 2, 2013. The charges are in connection to an alleged Al-Qaeda-inspired plot to explode a bomb at the B.C. Legislature on Canada Day.

  • An improvised explosive device (IED) created with a pressure cooker filled with rusted nails is shown in an RCMP handout photo released to media, Tuesday, July 2, 2013. Mounties say they've arrested two Canadian-born suspects with an "al-Qaida ideology" in connection with an alleged plot to blow up the British Columbia legislature on Canada Day.

  • Contents (nuts, bolts, nails and washers) and other materials for the improvised explosive devices (IEDs) are shown in an RCMP handout photo released to media, Tuesday, July 2, 2013. Mounties say they've arrested two Canadian-born suspects with an "al-Qaida ideology" in connection with an alleged plot to blow up the British Columbia legislature on Canada Day.

  • Three pressure cookers to be used as improvised explosive devices (IEDs) are shown in an RCMP handout photo released to media, Tuesday, July 2, 2013. Mounties say they've arrested two Canadian-born suspects with an "al-Qaida ideology" in connection with an alleged plot to blow up the British Columbia legislature on Canada Day.

  • Security guards watch over the legislature grounds in Victoria, Tuesday, July 2, 2013. Mounties say they've arrested two Canadian-born suspects with an "al-Qaida ideology" in connection with an alleged plot to blow up the British Columbia legislature on Canada Day.

  • An exterior view of the British Columbia Legislature in Victoria, B.C., on Friday August 26, 2011. Mounties say two people with "al-Qaida ideology" planned to blow up the British Columbia legislature on a national holiday.

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