EXCLUSIVE: It was one of the hottest scripts on the Black List a few years ago based on one of the most intriguing crimes in Australia over the last 50 years, and it just found a home with Phoenix Pictures Chairman/CEO Mike Medavoy. The company will produce A Country of Strangers from screenwriter Sean Armstrong about detective Geoff Harper’s 40-year investigation into the disappearance of three small children from an Australian beach.

In January 1966, three children, ages 4, 7 and 9 disappeared from Glenelg Beach near Adelaide, South Australia on a holiday. The Beaumont sibling case was the largest police investigation ever undertaken by Australian authorities. The children’s disappearance resulted in a nationwide search, shaking the moral fabric of the country and destroying the Beaumont family from within. The case also changed the psychology of the country in that after this case, parents in Australia were afraid to allow their children to go freely out of the house.

“After these crimes, parents thought twice,” said Armstrong, who explained to Deadline the genesis of his work on the screenplay which included travelling to Australia to do all his research. “I was on the Internet and saw a picture of these kids the year before they were taken and starting reading about them and the case and then just fell down the rabbit hole. The majority of what is written is true, but there are so many theories about what happened to these kids, depending on who you talk to. I did a lot of pacing in my room to figure out how to end this. Then I had a eureka moment. There an epilogue to the story that I really wanted to write, and I did. Mike Medavoy produced some of my all-time favorite movies, and Country could not be in better hands.”

Medavoy, of course, produced Zodiac as well as the psychological thrillers Black Swan and Shutter Island. He was also at Orion when they developed The Silence of the Lambs. With script in hand, Phoenix will next hire a director.

“This story had the entire country upside down,” said Medavoy. “And the kind of fear that parents have about losing their children to some kind of maniac will touch everyone. It’s the ultimate nightmare, and of course, in this one there is a surprise ending.”

Phoenix recently produced the eight-part global-event series The Long Road Home, based on Martha Raddatz’s best-selling novel about a platoon of soldiers who were ferociously ambushed in Baghdad and the rescue missions that followed. The series will premiere on National Geographic in early November.

Along with Medavoy, Edward McGurn and Michael Peterson will produce A Country of Strangers.

Armstrong is repped by Reed Baumgarten at Exile Entertainment and attorney Jeff Frankel at McKuin Frankel Whitehead.