Where to find the Facebook page about Sister Cathy shown in Netflix's The Keepers

Sister Cathy's body was discovered months later, but almost 50 years later no one has been found guilty of her murder.

Much of the series follows Gemma and Abbie's efforts to uncover what happened to their teacher.

During the course of their investigations, they set up a Facebook group, Justice for Catherine Cesnik and Joyce Malecki, in an effort to encourage people to talk about the murders of Sister Cathy and Joyce Malecki (a young woman who lived just three miles away from Cesnik and went missing four days after Cesnik was reported missing).

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The Facebook group is closed, but you can view some of the discussions or the description of the case, and request to join if you would like to post or comment.

The page also contains links to previous reports, information about who to contact with information and advice for people affected by the issues.

The group also has its own website, whokilledsistercathy.org, which includes details of the case and ways to get in touch.

Abbie Schaub (left) and Gemma Hoskins (right), former pupils of Sister Cathy who have set up a Facebook page to try and encourage more people to come forward with information

It's important to point out that these sites are independent of documentary The Keepers – although as director Ryan White says, both Gemma and Abbie are very aware of the extra attention their investigation will receive as a result of the Netflix series.

"Gemma was by far the most excited to have the documentary crew calling her," he tells RadioTimes.com. "Gemma does not shy away from attention, and that’s what’s incredible about her. Over the past three years she’s managed to create a very public conversation about what happened at her high school.

"Abbie is a little more reserved, a little more private and a little more suspicious. We had to win Abbie over a little bit more, and my personal connections to Baltimore really sold it to Abbie."

White's mother is from Baltimore, and his aunt was actually taught by Sister Cathy at Keough.

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Director White and producer Jessica Hargrave have spent the past three years working on the series, and so have been able to see how the pair have increased the online discussion surrounding the case.

“They intended to solve a murder, and what they did is they created a safe community for all of these women and men of a certain age to find people who believed them,” White says. “That’s been really powerful to witness as a filmmaker.”

He knows, too, that the series will bring even more exposure.

"I think Gemma saw this documentary as an opportunity to take this Facebook group, which was pretty contained to Baltimore at that point, and broaden it to something bigger," he says. "Since we announced the series, I talked to her the other day and she said that hundreds if not thousands of people are asking to join that group. We’ll see what happens over the next few months with her Justice Facebook group, but I think that’s what she wants."

And the page has already generated significant results, White adds: "The more people who join, the more people who potentially have information. You’ll see that in the series; we’ll have gone down one course and then all of a sudden Gemma will get a new email or Facebook message saying, ‘I know who killed Sister Cathy’, and then we end up on a whole different track.

"I think the Facebook page has allowed secrets to be unveiled in a lot of ways."

The Keepers is available to watch now on Netflix