Firstly send a notice to your in-laws to return the jewellery and other stridhan as soon as possible.
If they do not send within such and such date then you may file a criminal case against them.
File an FIR against your in-laws for criminal breach of trust, dishonest misappropriation of property under Section, 404, 405, 403 of the Indian Penal Code, 1860.
Economic abuse is interpreted as denying access to her belongs, her property, denying her basic financial resources, her financial rights, any stridhan etc.
If you are legally not divorced then you can make this a domestic violence case and you can make a complaint for the same to a mahila police station. If matter worsen then file a case of economic abuse- domestic violence against your in-laws.
Or you can file a civil suit for recovery of movable property and claim your stridhan form them under Section 7 and 8 of the Specific Relief Act, which deals with ÒRecovery of specific movable propertyÓ
You can file a suit for recovery of specific property under Order XXXVII of the Code of Civil Procedure, 1908, to get a court order against the in-laws to return back the stridhan.
Section 405 of Indian Penal Code, ÒCriminal breach of trust.Ñ
Whoever, being in any manner entrusted with property, or with any dominion over property, dishonestly misappropriates or converts to his own use that property, or dishonestly uses or disposes of that property in violation of any direction of law prescribing the mode in which such trust is to be discharged, or of any legal contract, express or implied, which he has made touching the discharge of such trust, or wilfully suffers any other person so to do, commits Òcriminal breach of trustÓ.
Reference: Section, 404, 405, 403 of the Indian Penal Code, 1860;
Section 7 and 8 of the Specific Relief Act;
Order XXXVII of the Code of Civil Procedure, 1908