Section 306 - women burnt death case

Inputs: Session Trial . Women with more than 7 years of marriage (6 year son) - suicide by burning- three days in hospital- death fourth day . FIR (on 4th day) named five people - husband, FIL, devar (living same house), nanad & nandoi (living same town but separately) . Chargesheet against only husband in 498A/306(since 1.5 yrs in custody), others lack of evidence . False allegation by mother, father and brother of deceased -"they didn't like daughter hence tortured and killed her". Also told that accused had fight over owning pressure cooker and hence killed her. All vague statements . Deceased working woman who even came home late at night after work- hence no possibility of torture . No neighbors are against us.They know we're innocent Question- Is the vague accusations by the family of deceased enough to convict someone for such serious charges.Does the onus of proof lie on us or on them? Can the remaining four (not chargesheeted) be dragged into this just because of false allegations? .