US authorities have been struggling to find a motive to the bloody high-school shooting which left 10 dead on a Native American reservation in Minnesota.
Weise shot dead five fellow students including Thurlene Stillday (in pink)
Jeff Weise, 16, shot dead his grandfather and his grandfather's partner before killing seven people at his school and finally himself.
Theories range from the teen's reported neo-Nazi leanings to school bullying and a troubled family background.
It was the worst US school shooting in six years since Columbine.
The shootings appeared to have been planned in advance, although the killings at the Red Lake High School itself appear to be random, the FBI said.
Weise appeared to be acting alone, it added.
His aunt, Kim Desjarlait, said she could not believe at first her nephew was the shooter.
"It wasn't the boy I knew and I had to confirm it," she told local television. "I was shocked once I knew exactly who was the killer."
RED LAKE VICTIMS
Daryl Lussier, 58, Jeff Weise's grandfather
Michelle Sigana, 32, Daryl Lussier's partner
Alicia Spike, 14, student
Thurlene Stillday, 15, student
Chase Lussier, 15, student
Chanelle Rosebear, 15, student
Dwayne Lewis, 15, student
Derrick Brun, 28, security guard
Neva Winnecoup Rogers, 62, teacher
Weise spent the first years of his life in the state's main city, Minneapolis, before moving to the reservation 330 miles (530km) to the north.
Weise's father committed suicide and his mother was living in a Minneapolis nursing home because she suffered brain injuries in a car accident, reports say.
Described as a loner who may have been teased at school, Weise is reported to have expressed admiration for Adolf Hitler on a Nazi website.
But the FBI said on Tuesday it had not determined if the writer was Weise.
The 300-strong school in Red Lake - close to the Canadian border - remains closed.
Seven other people were hurt in the incident.
Two 15-year-olds remain in critical condition in Fargo, North Dakota, with gunshot wounds to the face.