THE mystery surrounding the final resting place of two best friends who vanished almost 20 years ago when they were just 16 years old is yet to be solved.

But a series of Polaroid photos showing US murder victims Lauria Bible and Ashley Freeman bound and gagged by their accused killers has led to a man finally being identified and charged in relation to their deaths.

Ronnie Dean Busick was charged on Monday with four counts of first-degree murder, two counts of kidnapping and one count of first-degree arson in relation to the deaths of an Oklahoma couple and the disappearance of their 16-year-old daughter and her friend.

The 66-year-old is accused of fatally shooting Danny and Kathy Freeman, whose bodies were found in their burning home in Craig County on December 30, 1999. Investigators believe the couple’s daughter, Ashley Freeman, and her friend, Lauria Bible, were killed later, though their bodies were never found.

Mr Busick said he doesn’t know where the missing victims are but that he’s willing to speak with their families. He made the comments as he arrived at an Oklahoma jail on Wednesday after being extradited from Kansas.

“If he wants to talk to the family, he must know something,” Lauria’s mother, Lorene Bible said.

The charges come years after the initial investigation went cold, but authorities said a review in recent years uncovered new evidence, including witness statements linking Mr Busick and two other men to the killings. Warren Phillip “Phil” Welch II and David Pennington were the two other men named in the probable cause affidavit as “being involved in the murders and missing girls” but have since died.

In December 2017, Craig County Sheriff Heath Winfrey provided investigators with previously unknown notes and documents he discovered referencing the Freeman/Bible case. The previous sheriff’s administration had reportedly stashed the cache of information which also included the names of witnesses “that may possess information”.

It turned out that more than a dozen people with information about the grisly crimes had kept silent for almost two decades, some out of fear for their own lives, according to a court affidavit obtained by KFOR. Several witnesses claimed that the accused killers kept Polaroid photos of their victims as trophies.

There were rumoured to be about a dozen pictures, secreted away in a soft leather briefcase, The Washington Post reported. In some images, the missing teens were bound and gagged, thrown together on a bed, facing one another. Others showed the girls duct-taped to chairs.

One witness told police that she had previously seen the photos and that “in some of the Polaroids she observed Welch lying next to the girls” in a bed she recognised as his.

The woman said she confronted Welch about it and he told her, “Don’t you ever tell anybody or you will end up in a pit in Picher [Oklahoma] like those two girls,” Fox2now.com reported.

She said Welch threatened to kill her and her children several times, and throw them in the same pit as the two girls.

Another witness told investigators while he and his mother were living with Pennington, Welch and Pennington showed him the Polaroids of the girls and “told him that they killed the girls by strangling them”.

Although law enforcement in Oklahoma never discovered the photos, the lost images were burned into the memory of enough witnesses to serve as vital clues to unlocking a horrific cold case that had stumped investigators for 18 years.

Authorities said several witnesses alleged the men killed the Freemans over money owed for drugs.

According to an affidavit, one witness said: “Busick told him about how the girls were tied up in a trailer house in Picher where they were raped and tortured.”

Authorities believe the teenagers might be buried in a pit near Picher, a former mining boomtown in Oklahoma that has largely been deserted because of pollution. The area is about 150km northeast of Tulsa.

“It’s missing 18 years, you know,” Lauria’s uncle, Lonnie Leforce, said.

“I never got to see the girl at her 18th birthday, 21st, graduate high school, college, none of that stuff.”