Woman uncovers HEINOUS crimes of her ‘charming’ grandfather – who physically and sexually abused his own children while posing as a neighborhood nice guy – as she attempts to unravel his terrifying links to multiple unsolved MURDERS

A woman has launched a chilling investigation into her step-grandfather’s sexual and physical abuse, as she questions whether his crimes could have escalated into multiple murders.

Sierra Barter, from California, has become a central figure in Max’s upcoming four-part docuseries, titled The Truth About Jim, as she confronts her family’s traumatic past.

The amateur investigator will begin unraveling the horrific abuse suffered by family members at the hands of Jim Mordecai, who was to most a respected teacher in the San Francisco Bay Area.

But the family have now detailed their suspicions that the former patriarch, who died in 2008, could be responsible for a string of deaths that have gone unsolved for decades.

The amateur investigator will begin unraveling the horrific abuse suffered by family members at the hands of Jim Mordecai, who was to most a respected teacher in the San Francisco Bay Area.

Many believed that Jim “seemed like a really nice teacher,” but this was certainly not the full story.

“There are still a lot of people who look up to him, but it’s much darker,” one woman admits ominously.

Sierra then explains, “My step-grandfather was a man named Jim Mordecai. I’ve heard horror stories about him all my life.’

Jim was accused of sexual and physical abuse, including extensive beatings, leaving his family ‘terrified’.

“He was either the most charming man you would ever meet or he was your worst nightmare,” another woman added.

The trailer features Jim casually walking around the family living room as his own stepdaughter candidly reveals, “Being sexually abused by your stepparent who happens to be a teacher… it just shut me down.”

And it appears it was Sierra’s mother Shannon Barter who first said she thought Jim’s crimes could have been even more sinister.

Shannon sits with her head in her hands and mumbles, “I’m just trying to figure out when I started thinking he killed people.”

Sitting with her head in her hands, Sierra’s mother mumbles, “I’m just trying to figure out when I started thinking he killed people.”

Many believed that Jim “seemed like a really nice teacher,” but this was certainly not the full story

“There are still a lot of people who look up to him to this day, but it’s much darker,” one woman admits ominously

“It wouldn’t shock me if Jim had killed a few women.” I’d probably be shocked if he didn’t do it,” his stepdaughter reveals.

The clip then cuts to Sierra’s two investigative committees, mapping the locations of the Mordecai family homes in relation to both the Santa Rosa Hitchhiker murders and the Zodiac victims.

Between 1972 and 1973, seven women known to be hitchhikers were found dead in California; three of the victims had been raped and three were too decomposed for investigators to determine.

An eighth likely victim also disappeared, but her body was never located.

The massacre became known as the Santa Rosa Hitchhiker Murders.

The series of murders was at one point even linked to the infamous Zodiac Killer, who operated in Northern California in the 1960s and 1970s.

Jim was accused of sexual and physical abuse, including extensive beatings, leaving his family ‘terrified’

“He was either the most charming man you would ever meet or he was your worst nightmare,” another woman added

The clip then cuts to Sierra’s two investigative committees, mapping the locations of the Mordecai family homes in relation to both the Santa Rosa Hitchhiker murders and the Zodiac victims.

But because these murders did not involve rape, nudity or dumping of victims off the road, the connection was never firmly established.

Both cases are currently still unresolved.

Sierra closed the trailer by saying, “It sounds crazy, but this is reality. Someone’s grandpa was the serial killer, was it mine? Don’t know. But someone’s grandfather did.’

In the documentary, she will gather evidence, collect testimonies from witnesses and ultimately hand over her findings to police “in hopes of convincing them to investigate and help her family step out of Jim’s shadow.”

Max’s The Truth About Jim is released on February 15