What happened to Sarah's brother when he ran?

Sarah locked her brother in a closet ad he died there when she ran.

Explanation:

Sarah locked her brother in a cupboard thinking that she will return in sometime. But this didn't happen. Her brother died there by the time she returned to get him. He was not taken to camp.

This incident leaves Sarah broken heart and she grew up with that broken feeling. Later she died in a car incident.

This shameful incident happened in Paris in France in 1942.

A novel named as Sarah's Key was published in 2006.

On July 16, 1942, Sarah's home was raided by French police. Police arrested Sarah along with her parents but her her brother was left as he was locked in a closet. Later they were sent to an enclosed stadium from where Sarah tried to escape to save her brother.