Wife filed case and asking dowry without signing on mutual divorce

2 days back my sister in law has given a petition to the local police station stating to provide all her gold & dowry. Now we have agreed to give everything but she has to sign a mutual divorce. But now the police is pushing us to give off the gold without getting our advocates involved. We insisted on giving all her belongings after the 2nd motion at the family court is completed. What can I do on this? I want to make sure that she doesn't file any more cases as well as signs on the mutual divorce agreement. Only after that, her belongings will be handed over.