The accused had been hoping to obtain their conditional release but instead were forced to remain behind bars as their bail hearing was postponed until next week.
The suspects, Francois-Vivier Gagnon, 22, Genevieve Vaillancourt, 25, Vanessa L'Ecuyer, 22, and Roxanne Belisle, 23, smiled and acknowledged family and friends packing the courtroom as they stood in the prisoners' box.
The visitors' gallery, packed with some of their friends, fans and family, showered the accused with hearty applause as they were led away.
As they walked out in handcuffs, family members blew kisses and mouthed words of support. One suspect's younger sibling sobbed.
The four have been detained since turning themselves in to authorities Friday and were arraigned over the weekend on several charges: perpetrating a terrorist hoax; mischief of more than $5,000 and conspiracy to commit mischief. Gagnon is also charged with possession of a prohibited weapon for allegedly having a butterfly knife in his possession.
The charge of perpetrating a terrorist-related hoax carries a maximum five-year prison term. The charge was created through with an amendment to the Criminal Code after the events of 9-11 and it has been used previously by the Crown, prosecutor Steeve Lariviere said Monday.
He said he will oppose the bail request, on the grounds of ensuring public confidence.
The delay Monday was caused by a procedural problem. The defence had not received the Crown's evidence and both sides needed more time to prepare their case.
The three women and one man are accused of tossing smoke bombs into various subway stations last Thursday, shutting down service during rush hour. It caused a frustrating morning commute for tens of thousands of Montrealers and prompted a mass evacuation of the transit system.
The Crown declined to go into specifics about the case, such as whether the four were believed to belong to a specific group.
"(The hoax) was basically linked with a public service and that's why this charge was brought forward," said Lariviere.
"It's to make sure that public services are not held hostage by that type of infraction."
There were tense scenes outside the courtroom Monday.
Some protesters accused the media of being biased against their cause and they obstructed television cameras seeking to get footage.
They repeatedly swore at journalists who asked for interviews.
Some of their anger stemmed from the fact that one of the suspects had been misidentified in various media before the arrests were made. One of the names circulating in media reports never appeared on the charge sheet.
Lawyer Veronique Robert, who currently represents two of the accused, said the suspects all come from good families. She said outside the Montreal courthouse that the four are holding up well, considering the circumstances.
"They're not thrilled but they're not defeated either. They're not falling apart," Robert said.
The four suspects will have a full day to argue for bail on May 23.
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