Investigators are trying to piece together details of Friday's shooting spree at an elementary school in the US state of Connecticut, which killed 20 children and eight others.

Connecticut State Police Spokesman Paul Vance said detectives are still scouring Sandy Hook Elementary School, accumulating evidence and information.

Vance added that the process could take another day or two, if not longer.

"We've done everything we need to do to literally peel back the onion, layer by layer, and examine every crack and crevice of that facility and that does not .... exclude .... the outside of the building. The outside of the building is also part of the crime scene, every vehicle in that lot, so it's going to be a long, painstaking process."

Investigators are trying to learn more about the gunman, 20-year-old Adam Lanza, who police said forced his way into the school.

Witnesses said Lanza didn't say a word as he burst into a classroom, started shooting, and later killed himself.

Law enforcement officials said Lanza shot his mother, Nancy Lanza, drove to the school in her car with at least three of her guns, and opened fire in two classrooms.

The shooting spree has drawn widespread condemnation from across the world with condolences offered to the victims.

Chinese President Hu Jintao has sent a message of condolences to U.S. President Barak Obama following the shooting incident.

Hu Jintao expressed profound sympathy with and faithful solicitude to the U.S. government and its people over the tragedy.

The attack has also evoked thoughts in the streets of China and Australia.

"I think it's really shocking. Because I think perhaps it's related to the security of their society. I think perhaps a lot of Chinese would see it this way. Perhaps U.S. society's policy on supervision of guns is not very strict."

"I think it's dreadful. I would hate for my children to be brought up in a society where they thought they had the right to bear arms normally."

Friday's attack at the elementary school was the latest of several mass shootings in the US this year.

The incident approached the deadly scope of the Virginia Tech university massacre in 2007 that left 32 dead. 

From CRIENGLISH.com