Police said that recently-discovered case notes could help them make great strides in the case of two Oklahoma teens who vanished 18 years earlier.

Lauria Bible and Ashley Freeman (pictured left and right) celebrated Bible’s birthday with a sleepover at Freeman’s home on December 29, 1999. The next day, Freeman’s parents, Danny and Kathy Freeman, were found shot to death in the burning home and the girls, both 16 at the time, were nowhere to be found, according to KOTV.

The Oklahoma State Bureau of Investigation (OSBI) announced on December 29 that the emergence of the case notes could signal “a turning point in the case.” The Joplin Globe noted that OSBI is working with the District 12 District Attorney’s Office and the Craig County Sheriff’s Department on the 1999 cold case.

“The new sheriff [Craig County Sheriff Heath Winfrey], when he was moving in, found this box with information pertaining to the case,” OSBI spokesperson Jessica Brown revealed in a statement.

Officials couldn’t divulge what the notes contained but claimed they provided “extremely valuable” information.

“This information has produced leads that have produced additional leads,” District 12 District Attorney’s Office investigator Gary Stansill told Tulsa World.

As CrimeOnline reported last week, OSBI is offering $10,000 for anyone who provides credible information about this case. Meanwhile, a private reward of $50,000 is also being offered.

READ More: Can you help solve this cold case? Reward offered to solve murder of parents, missing teens

Investigators said the case is active, and they’re interviewing several people with knowledge about the double homicide and the girls’ disappearance. They told KOTV that, “the investigation has definite course and direction.”

[Featured Image: Lauria Bible and Ashley Freeman/National Center for Missing and Exploited Children]