The Virginia Tech gunman Cho Seung-Hui was so quiet as a child that his parents feared he was mute, according to his devastated family in South Korea.

Cho’s uncle explained that the loner “didn’t talk much when he was young. He was very quiet, but he didn’t display any peculiarities to suggest he may have problems”.

His uncle, who asked to be known only as Kim, said the family were struggling financially in America. Cho set out his hatred of the wealth and hedonism of classmates on a video he sent to American network NBC in the middle of his killing spree.

Kim had spoken to his sister, Cho’s mother, regularly since the family moved to Virginia. “She just talked about how hard she had to work to make a living, to support the children,” he said. “I am devastated. I don’t know what I can tell the victims’ families and the US citizens. I sincerely apologise ... as a family member.”

The killer’s family moved to America in 1992 when Cho was eight years old. They immigrated to Virginia in hope of providing Cho and his sister with a good education and to make a better living. Cho’s parents had bought a tiny bookshop in Seoul soon after they were married, but they were struggling to make a profit from the business, according to Kim.

Cho’s grandfather said the family had very little money when they boarded the plane to America. They had been living in a poor area of Seoul, in a basement flat that now stands abandoned, it was reported in South Korean newspaper Chosun Ilbo.

His parents now run a dry cleaners in Centreville, Virginia. Korean media reports suggested that they were taken to hospital on learning of their son's rampage.

Cho’s sister, Sun Kyung Cho graduated with an economics major from the Ivy League university Princeton in 2004. While she was there, she was accepted onto three government internships, two at the State Department and a third placement, sponsored by Princeton, at the US embassy in Bangkok, Thailand.

Sun Cho now works as a contractor for the US State Department office that oversees reconstruction in Iraq. The Iraq Reconstruction Management Office is responsible for billions of dollars of American aid, a State Department staff directory says she works from an annexe near the office headquarters in Washington.

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