London (CNN) Matt Linsey's face is peppered with minute scars from the shrapnel and debris that hit him, as he recalls the split-second decision he and his two children made to run, rather than hide, just after the first of two bombs went off.

"The bomb went off and they both were running toward me," he said. "I knew there'd be another bomb because there always is with these things."

His instinct was right, but it was as they fled that the second blast hit his children, Daniel and Amelie, detonating near the elevators on the third floor of the upmarket Shangri-La hotel in Colombo, Sri Lanka

The 61-year-old US investment banker is both numb in grief after their deaths and tormented by what he could have done differently, faced with the impossible task of protecting his children from such murderous intent.

"Maybe I should have stayed and covered them with my body," he said of the Easter Sunday suicide bombings that struck seven buildings in three Sri Lankan cities. Officials say more than 300 people were killed and hundreds were wounded.

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