MAKHACHKALA, Russia (AP) Russian agents placed the elder Boston bombing suspect under surveillance during a six-month visit to southern Russia last year, then scrambled to find him when he suddenly disappeared after police killed a Canadian jihadist, a security official told The Associated Press.

NPR: Russia Had Elder Boston Suspect Under Surveillance

Law officials in New York with knowledge of the investigation told The Associated Press the attack was to take place on the Canadian side of the border.

WSJ: Suspect in Canada terror plot denies charges