A student on Monday killed two of his grandparents, then went on a shooting rampage at his Minnesota high school, killing seven people and wounding as many as 13 others before killing himself, officials said.
FBI Special Agent Paul McCabe told reporters the dead include a female teacher, a male security officer and four students at Red Lake High School.
"We believe that one of those students is the shooter," McCabe said.
The FBI office in Minneapolis later said two more wounded students had died.
The school, about 240 miles north of the Twin Cities, was evacuated and locked down, McCabe said.
"At this time, we believe he was acting alone," he said, refusing to comment on a possible motive, adding, "It's far too early in the investigation."
The slain students were shot in one room, he said.
"Apparently, he walked down the hallway shooting and then he entered a classroom, he shot several students and a teacher, then himself," said Roman Stately, with the Red Lake Fire Department, who arrived at the high school moments after the shootings.