A group of "murderous misfits" planned a massacre on Valentine's Day in Atlantic Canada's largest regional shopping mall but the alleged plot was foiled by police after an anonymous tip-off, the justice minister said on Saturday. Police charged two people with conspiracy to commit murder and released a third suspect in the alleged plot to shoot as many people as possible in the Halifax Shopping Center. A fourth man linked to the plot was found dead in a house in Halifax, police said. "Based on what we know so far, it would have been devastating, mass casualties would have been a real possibility," Justice Minister Peter MacKay told reporters.