Clash between two groups over a petty issue claimed one life.    According to details, two groups following a quarrel clashed over a petty issue here in Nasarabad area.    Resultantly, a 23-year-old boy Dawood Khan Usmankhail sustained critical injuries. He was rushed to DHQ civil hospital Zhob, where he succumbed to his injuries. The body was later handed over to relatives after fulfilling medico-legal formalities. Police have registered a case against Ajab Khan and Fateh Khan and started further investigation.