TORONTO — Canadian police foiled a plot by two suspects who were planning to go to a mall and kill as many people as they could before committing suicide on Valentine’s Day in Halifax, a senior police official said.

The official told The Associated Press on Saturday that police acted quickly after receiving information from the public on the Crime Stoppers tip line.

A 19-year-old male suspect shot himself to death after police surrounded his home, the official said. A 23-year-old woman from Geneva, Ill., 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.

The official said the suspects used a chat stream and were apparently obsessed with death and had many photos of mass killings. Police and Canadian Justice Minister Peter MacKay said the plot was not related to Islamic terrorism.