Tom Teves and his wife Caren at the preliminary hearing for James Holmes at the courthouse in Centennial, Colorado.
Their son Alex died in the shootings in July last year protecting his girlfriend from the gunfire.
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Ursula Keogh, 11, went missing on Monday around 3.30pm. She was dressed in her school uniform.
"My sincerest apologies to everyone who purchased tickets and were planning to come to the upcoming shows."
His comments at the Defence and Security Forum on Monday came after a £20 billion black hole in the budget for the next decade emerged.