Possible legal action against my son-in-law for harassing my daughter?

You should draft a complaint in writing and get it registered at the nearest police station under section 498A of the Indian Penal Code and under the protection of women from Domestic Violence Act. The police shall give you a diary number.

Thereafter, they are under an obligation to register an FIR with respect to the cognizable offences. If the same is not done, you can write a complaint addressed to the SHO of the police station asking them to register the FIR.

If no action is taken even after that, then you can file an application under section 156(3) of the code of criminal procedure and a complaint under section 200 of the code to the magistrate in the competent court praying for registration of FIR and to take cognizance of the matter.

With respect to the CAW cell, as you have stated you have already registered your complaint there so you would have the diary number. All this information can be mentioned in the complaint to be filed before the magistrate in the competent court.

Mention all the facts in detail to establish instances of domestic violence and for dowry.

Your daughter can even claim maintenance and right of residence under the code of criminal procedure and under the protection of women from Domestic Violence Act.