The police have tightened security in the Muslim-dominated areas here following the death of a person who was injured in a group clash on March 14. Irfan Mohammad Aaron succumbed to his injuries at a private hospital in Hyderabad on Friday. Five persons received serious injuries after two groups clashed over the ownership of 1.25 acres of prime land at Hagarga village on the outskirts of the city on Wednesday night. All the accused named in the first information report are absconding.