Is there any secret behind the Mangal Sutra?

Aditya told that his mother was a tortured woman. But the way she behaves with Sugni or haunting a Mangal Sutra from a dead woman is not showing what she was told. Is that a mistake of the PH or is there any secret there?

She got the respect to be the Thakurayene. Her children got the name and money of Thakur.But what did that Reshm got?She was also a victim of Aditya's Dad.

Did Aditya's Mom committed any crime? Such as murdering Aditya's Dad or Reshm?Is that Mangla Sutra an alibi?

Whatever it is I'm finding the family fishy.What they are saying they are not that. There is more than what they are showing.