Zaid al-Hilli told ITV News that his family was "very encouraged" by the arrest made in the investigation into the death of his brother and his family.
"We are very encouraged by the recent developments. Hopefully we will get to the truth," he said.
But he added: "I don't want to raise my hopes."
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ITV News correspondent Dan Rivers was taken, by regime minders, to the hospital where those who were affected by the attack were treated.
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The composer says schools are failing to see how music can support behavioural and academic success.