Update: 4:15 p.m.

Canadian police have foiled a plot by three suspects who were planning to go to a mall in Halifax, Nova Scotia, and kill as many people as they could before killing themselves on Valentine's Day, police said Saturday. One suspect fatally shot himself as police moved in to arrest him, and an American suspect confessed to the plot when she was arrested at the Halifax airport, a senior police official told The Associated Press.

Police and Canadian Justice Minister Peter MacKay said the plot was not related to terrorism.

"This appeared to be a group of murderous misfits that were ... prepared to wreak havoc and mayhem on our community," MacKay said Saturday. "The attack does not appear to have been culturally motivated, therefore not linked to terrorism."

The Royal Canadian Mounted Police said friends Lindsay Kantha Souvannarath, 23, of Geneva, Illinois, and Randall Steven Shepherd, 20, of Nova Scotia, have been charged with conspiracy to commit murder.

Nova Scotia RCMP Commanding Officer Brian Brennan said the suspects planned to go to the Halifax Shopping Center and kill as many people as they could on Saturday, Valentine's Day, before taking their own lives.

He told a news conference that police found three long-barreled rifles in the home of a third suspect, a 19-year-old who died before he could be arrested. He did not elaborate on how the suspect died.

But a senior police official told The Associated Press that the 19-year-old male fatally shot himself early Friday after police surrounded his home in the Halifax suburb of Timberlea.

The official said the American woman had prepared a number of pronouncements to be tweeted after her death. Shepard was also arrested early Friday at the airport where he went to meet his friend, police said.

The suspects used a chat stream and were apparently obsessed with death and had many photos of mass killings, said the official, speaking on condition of anonymity because he was not authorized to speak publicly.

Police acted quickly after receiving information from the public on the Crime Stoppers tip line. The two suspects are due in court on Tuesday.

At the home of the male suspect, police saw two people leave the house who they determined were the 19-year-old's parents and pulled them over on a traffic check. They then called the suspect.

The man told police that he didn't have any guns but shot himself as he was on his way out of the house, the official told the AP.

A neighbor said the 19-year-old had not mixed with others in the neighborhood in recent years.

"He was one of those people who kept to himself, not a people person," said the neighbor, Steven Greenwood.

The official said police worked with Canadian border officials to find the female suspect on her flight as she was making her way from Chicago.

Police in Geneva, about 35 miles (56 kilometers) west of Chicago, searched Souvannarath's home on Friday night and seized several items. Geneva Police Cmdr. Julie Nash refused to describe the items or their potential value as evidence, saying Canadian authorities had requested that such information not be made public.

A former neighbor, Eva Schooley, moved into the same cul-de-sac a few months after the Souvannaraths in 2000 and lived across from them for about a decade. She recalled them as "very nice people" and said they participated in frequent block parties, Easter egg hunts and Halloween parties.

"My granddaughters ran around with Lindsay," she said. "Lindsay was a little strange. I think at one point she went kind of gothic on us for a while. She liked to dress in black, the whole gothic style."

Police said Friday they first received information a day earlier about a potentially significant weapons-related threat.

Tensions remained high in normally calm Halifax. Police responded to reports of shots fired at the Halifax Shopping Center on Saturday night, but backed off when it was determined that seven kids were playing with slingshots. Police tweeted that seven youths were in custody and said there was no active shooter.

— Rob Gillies, Associated Press. Jason Keyser in Chicago contributed to this story.

Earlier:

Police in Canada say they've foiled a Valentine's Day plot to carry out a mass shooting at a mall in Halifax, Nova Scotia.

Dan Karpenchuk, reporting from Toronto for NPR, reports that one person was found dead and three others taken into custody on Friday by the Royal Canadian Mounted Police in connection with the alleged plot, which authorities say was not related to Islamic terrorism. The suspects reportedly planned to kill as many people as possible before committing suicide.

The Associated Press quotes an unnamed police official as saying the RCMP acted on a tip that came in on a Crime Stoppers hotline.

A 19-year-old male suspect killed himself after police surrounded his home early Friday morning. The AP says: "a 23-year-old woman from Geneva, Illinois, was arrested at Halifax airport and confessed to the plot, the official said, adding that she had prepared a number of pronouncements to be tweeted after her death."

Police said two others, males aged 20 and 17 from Nova Scotia, were also arrested in connection with the plot, but their exact role was still being investigated. The 17-year-old was wanted for threatening to shoot up a high school and had an outstanding warrant.

The AP, quoting the unnamed officials, says "the suspects used a chat stream and were apparently obsessed with death and had many photos of mass killings."

The Halifax Chronicle Herald quotes Canada's Justice Minister Peter MacKay as praising law enforcement in acting quickly to avert a tragedy.

"Based on what we know so far, it would have been devastating," MacKay said. A day known to represent love and affection could have taken a much different meaning today had it not been for the exceptional efforts of the combined law enforcement community."

"While this particular incident doesn't appear to be motivated by terrorism, we believe, in particular, some of the online investigations that are required to avert this type of activity do require changes in the legislation and that's why current legislation is before Parliament," MacKay said.

"This appeared to be a group of murderous misfits that were coming here or were living here and prepared to wreak havoc and mayhem in our community," he said.

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This story has been updated.