Melissa McCarthy Believes JonBenét Ramsey Wasn't Killed by Her Family

Melissa McCarthy says playing JonBenét Ramsey's mother in a true crime drama forced her to make up her own mind about the murder ... and she doesn't believe anyone in the family did it.

The actress plays Patsy Ramsey in Netflix's upcoming "The Murder of JonBenét Ramsey" ... and she tells Variety she developed a lot of compassion for the family while working on the project.

Melissa says the case became something people treated almost like a sport ... with everyone offering up their own theory as if it were fact.

She says she couldn't play Patsy without deciding for herself what she believed happened.

Her gut instinct? "My heart says no one in the family could have done that."

Melissa admits she may not have the right to make that call ... but says she needed to settle it in her own head before taking on the role.

She actually wanted nothing to do with the project at first ... but changed her mind after digging into the case and what she describes as the lack of humanity shown to the Ramsey family.

Melissa says she even had to confront her own role in that ... remembering seeing tabloid coverage back in 1996 and judging Patsy over how JonBenét was dressed.

Now, she says she hopes the series makes other people look back and realize they may have gotten swept up in the same thing.