The Rajnagar police on Friday arrested three persons of a family at Rajnagar village in Kendrapada district for allegedly beating one of their relatives Ratnakar Mallick (70) to death on Thursday night following a quarrel erupted between the two families over one-sided love. One Saroj Mallick, son of Abhaya Mallick, was in love with the granddaughter of Ratnakar and wanted to marry her. As Saroj was the cousin of the girl, family members of Ratnakar refused the marriage proposal, for which both the families used to quarrel most of the time. On the fateful night, Saroj with the help of his family members beat Ratnakar to death near the local Durga temple. Inquiry was on into the incident, police sources said.