![Missing Diana Quer's sister Valeria, 16, spends night in police cell for 'threatening their mother'](https://cdn.thinkwebcontent.com/news/images/400/foto28858.jpg)
Missing Diana Quer's sister Valeria, 16, spends night in police cell for 'threatening...
THE younger sister of missing Madrid sixth-former Diana Quer has been arrested for 'threatening' her mother.