Tanja Afra Maria Groen

Status:

Open

Missing From:

Maastricht, Netherlands

Summary:

Tanja Afra Maria Groen was an 18-year-old Dutch student who disappeared on the night of August 31–September 1, 1993, after leaving a hazing party at her student association in Maastricht. She was cycling to her room in Gronsveld, a distance of approximately 10 kilometers, when she vanished. Despite 33 years of investigation, thousands of tips, extensive searches, and a 1 million euro reward offered in 2021, her body has never been found. The investigation was officially closed in May 2026.

Vital Statistics

Circumstances of Disappearance:

Tanja Groen attended a hazing party at the Circumflex student association on Herbenusstraat in central Maastricht on the evening of August 31, 1993. She spoke with her mother by phone around 7:30 or 7:50 p.m., stating she would return to her parents' home in Schagen a day later than originally planned due to commitments during hazing week. Around midnight, Tanja left the party on her bicycle, intending to cycle to her student room in Gronsveld, approximately 10 kilometers away. She never arrived at her destination. Her bicycle was also never recovered. Tanja's classmates noticed her absence from classes that began on September 1, 1993. It was not until September 3, 1993, that a fellow student called her parents in Schagen to inquire whether Tanja had gone home early, prompting them to report her missing to police in Schagen that same evening.

Additional Details:

Despite a thorough and lengthy investigation spanning 33 years, no trace of Tanja was ever found. Police assumed a crime from the outset. Two main suspects emerged during the investigation: convicted murderer Willem S. (also known as the 'Killer van Lappegat'), who was at a nearby campground at the time of her disappearance—the same campground where the Groen family had vacationed; and Wim Smulders, a convicted murderer from Geldrop. Tire tracks found in Smulders' car were compared against Tanja's bicycle, but no conclusive match was established. Neither man was ever formally charged in connection with Tanja's disappearance. The case was also investigated for possible links to Belgian serial killer Marc Dutroux, particularly after clothing and toys were found during searches of Dutroux's properties. Tanja's parents examined items seized from Dutroux, but none belonged to their daughter. In 2012, a bicycle was recovered from the Maas River based on a psychic's information, but it did not belong to Tanja. In June 2014, human bones were discovered near Gronsveld, but forensic analysis confirmed they did not belong to Tanja. In 2019, a tip led police to search the Heugem Catholic Church cemetery in Maastricht in January 2020, but nothing was found. In 2021, crime journalist Peter R. de Vries established the 'De Gouden Tip' (The Golden Tip) Foundation, which successfully raised 1 million euros through crowdfunding—the highest reward ever offered in the Netherlands—to incentivize information leading to Tanja's discovery. Despite this unprecedented reward and thousands of resulting tips, no breakthrough occurred. Additional searches on the Strabrechtse Heide in Heeze and other locations under forensic-guided investigation in 2021-2022 also yielded no results. In 2026, information provided by a Belgian prisoner (Johan V.) claiming knowledge of Tanja's abduction, killer, and burial site proved unreliable and partially false. After 33 years of investigation—including DNA comparisons across Dutch and international databases, extensive excavations, and examination of over 1,000 tips—Dutch police and the Public Prosecution Service officially concluded their investigation in May 2026. However, authorities stated that concrete new information could reopen the case. The 1 million euros collected for Tanja's case was redirected to other cold cases and victim support initiatives. Tanja's parents, Corrie (mother) and Adrie Groen, have lived with uncertainty for over three decades, though they expressed gratitude for the attention and support received, particularly from Peter R. de Vries and his foundation.

Case Last Updated:

Nov 03, 2026