She can file in CAW,court or with police.
you have go there to give your statement, no matter what you do or tell if they decided to file chargesheet they will file, but provide all details of your version of the story.
you can give in writting to get FIR copy or file RTI and they have to give copy.
be polite and answer correctly and all members same version.
thats it, if in fir she said they gave dowry then ask police to file complaint on them 1st under dp3 act. and provide stridhan list if any