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It happened last night.- без изменения

I was a very dark night, but at about 11 pm two men  were seen by the person who lives nearby. 

The police was called. 

They arrived at 11.15, - без изменения

but nobody was found in the school. It seems that the burglars were very quick. 

Some computers were stolen. 

Two men have already been arrested. 

They are being questioning at the moment. I hope it is them!