Three persons have been killed when one of the groups hurled a hand grenade on the other at Sari Naurang area in Lakki Marwat on Thursday, district police. Ayub Khan and his brother Latif Khan exchanged hot words over property dispute when one of them threw hand grenade on the other. As result of explosion Ayub Khan, Latif Khan and Mehrab Khan died instantly. Police have registered case and started investigation.