11/04/2012 09:10 EST | Updated 01/04/2013 05:12 EST

Transit sweeps continue in wake of explosives probe

Transit sweeps and additional security are slated to continue on Metro Vancouver SkyTrains and buses during the Monday morning commute as the investigation continues into the bomb that was found on the tracks in Surrey on Friday.

"You will definitely see this going into tomorrow's commute and in fact for the first several days of the week," said Transit Police spokesperson Anne Drennan. "I think it's pretty obvious at a certain point, we're going to have to pull back."

Drennan says investigators are looking at the SkyTrain system and on the ground in Surrey for evidence, as well as following up on tips from the public.

"We have been conducting a thorough investigation into social media sites, looking for any potential threats, or any bragging that might go on about someone who might feel some pride or take some pride in what happened the other day," she said at a news conference Sunday afternoon.

"But as of yet, have come up with nothing."

The bomb has been described by experts as being crude, but dangerous.

Drennan says a passenger on the train spotted three canisters strapped together with tape on Friday afternoon and alerted a station attendant.

The explosive device was attached to canisters that were the size of fire extinguishers and could have been thrown onto the guideway or it's possible someone climbed up to the area, Drennan said.

Explosives technicians believe the object would not have detonated on its own but may have been electronically or manually set off, Drennan said.

The incident disrupted service on the SkyTrain system between the Scott Road and Gateway stations for about three hours.

Officials conducted a sweep of the entire transit system Saturday, leading to one false alarm.

Police shut down Main Street SkyTrain station for about half an hour after another suspicious package was spotted, but it turned out to be a purse with a wristwatch attached to the strap.