Police arrested chain snatcher how can I recover my gold ornaments

my family is attacked by the local goons and during the scuffle someone from the goons snatched a gold chain from my sisters neck. I made a complaint to the police. Police made those goons to come to the police station. But some people put pressure on my father that the family of those goons could harm my family. So I taken back the case. They gave a written apology letter. But they not returned the gold ornament. I want the justice, I want to reopen the case is it possible to do so.