Frances McDormand as Mildred Hayes in 'Three Billboards outside Ebbing, Missouri"
CNN —  

A woman is found murdered by the side of a road. Her grieving parent, upset that the killing remains unsolved, rents billboards asking police why no one’s been arrested in the case.

It sounds like the plot of “Three Billboards Outside Ebbing, Missouri.” But it’s the real-life case that inspired the Oscar-winning movie.

Now, investigators in Texas have raised the reward money in the 27-year-old case in hopes it’ll bring new leads to this unsolved mystery.

The case

The case began on May 14, 1991 when the body of Kathy Page was found inside her car in a ditch in Vidor, Texas,

Page, 34, had been strangled and police think her vehicle had been put in the ditch to make her slaying look like a car accident, according to a news release from the Texas Department of Public Safety.

The billboards

For years Page’s father, James Fulton, put up billboards along a stretch of Interstate 10 between Vidor and Beaumont, calling for justice for his daughter, according to the Beaumont Enterprise.

British writer-director Martin McDonagh saw the billboards during a bus trip through the South 20 years ago, and it stuck with him.

A scene from the movie "Three Billboards"

“It was this raging, painful message calling out the cops about a crime,” McDonagh told the British newspaper Express. “The title came from the concept and the concept came from that image, which stayed in my mind for years. What kind of pain would lead someone to do that? It takes a lot of guts – and anger.”

He took that message and turned it into “Three Billboards Outside Ebbing, Missouri,” about a woman who confronts the police over her daughter’s unsolved rape and murder. It won a pair of Oscars at the Academy Awards in March.

In the Page case, the Texas Department of Public Safety said this week it was doubling the reward offered in the case – it was $3,000 – up to $6,000 for information in the slaying.