Chilling unresolved case of 'pregnant' teenager who vanished from foster family

Life wasn’t easy for 15-year-old Willeke Dost, who went missing from her foster family back in 1992 and was never seen again.

She suffered a traumatic childhood - both of her parents died in a car crash in 1976 before she even made it to her first birthday - before she was then placed in a string of foster homes around the Netherlands.

After she went missing, accusations of abuse by her foster family, the Mulders, emerged and resulted in arrests, but nothing has ever been proven.

Now Marja West, a cold case investigator, has made it her mission to crack the mystery - and she believes she knows exactly what happened. Could she have been murdered by a mystery man?

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Interviewing more than 300 people who knew Willeke - she has revealed a new bombshell theory about a "predatory" man. "I know what happened that night Willeke disappeared,” she told The Sun.“The newspapers couldn't be more wrong."

At the time of her disappearance, she was living on a farm with a foster family in the rural village of Koekange with their daughter and two sons.

The schoolgirl left the farm early on the morning of January 15, 1992, riding a bicycle, but because there were no leads after she vanished, police assumed she’d run away.

One of Willeke's good friends was Geke Crediet and it was her mother Anneke who initially told TV reporters that Willeke had admitted to her daughter she was pregnant and had been sexually abused by her foster family.

Marja says that for the first five years Anneke told people she believed Willeke had run away to find her new life - but the Mulders were released without charge.

Now after speaking to hundreds of people who knew Willeke and listening to hours of audio tapes, Marja has built her own theory - and she doesn't believe she was abused by her foster family.

Marja is convinced she knows what really happened on the night Willeke disappeared: "In the weeks before she went missing, Willeke talked about a much older ‘boy’ named Sebastian, a fake name. "I found out that 'Sebastian’ was a predator, a man who later in life became a convicted murder."

Marja learned of 'Sebastian' through speaking to a police detective who investigated a man who murdered his wife. During interrogation, Sebastian had spoken of Willeke as if he knew her, according to the detective. Then, during his hearing, Sebastian taunted that he could have done the same to Willeke.

Marja is convinced that Sebastian was the older man Willeke had spoken about, and that he is behind her disappearance. Her next step is to find 'Sebastian'.

"I spoke to 300 people who knew Willeke and, like Anneke, I bent over backwards to find out what had happened to her,” she said. "I drove 93,000km in The Netherlands, in Belgium, Germany, Luxemburg and France, and I got help from inside the justice department.

"There are lots of children like Willeke that went missing. Some of them were never found. People don’t dissolve like an aspirin in water. Someone must know something. Families need answers and not to be left with doubt."