Clas Göran Lennart Svahn is a Swedish journalist, author and ufologist who has collected and investigated UFO reports for about five decades. A longtime reporter at the Stockholm daily Dagens Nyheter, he chairs the Archives for the Unexplained in Norrköping, a volunteer-run foundation that historian Greg Eghigian has called the most comprehensive archive on the global history of UFOs. Since 2023 he has also chaired UFO-Sverige, the national UFO organization of Sweden, and edited its magazine UFO-Aktuellt.

Svahn was born on April 12, 1958, in Mariestad and trained at the journalism school in Gothenburg before a career at Dagens Nyheter that lasted until his retirement, with ufology running alongside it. In 1984 he interviewed Karl-Gösta Bartoll, the Swedish Air Force officer who had led the 1946 search of Lake Kölmjärv during the ghost rocket wave, and Bartoll told him the object had largely disintegrated. Svahn's books include Domstensfallet (1989), written with Anders Liljegren about a 1958 Swedish close encounter, and Mötet i gläntan (1995), written with Gösta Carlsson about Carlsson's claimed 1946 landing encounter near Ängelholm. After more than a hundred hours of interviews, Svahn came to disbelieve that encounter, though he did not doubt Carlsson's conviction.

The archive he now leads was founded in Södertälje in 1973 by Håkan Blomqvist, Kjell Jonsson and Liljegren, became a foundation in 1980 and dropped its original name, Archives for UFO Research, in 2013 to reflect a wider remit. Under a 1986 agreement it manages the archives and library of UFO-Sverige, including roughly 20,000 Swedish sighting reports, and it holds copies of open Swedish Armed Forces UFO investigations dating to 1946. Svahn became its chairman in 2017. In a 2024 AFP report, he and Liljegren described themselves as "curious investigators of the unknown" rather than believers, and Svahn said the archive was building "depository knowledge" for researchers worldwide.

In February 2026 Svahn reached a large American audience on Jesse Michels's American Alchemy, recorded at the archive. According to the program, he had recently received clearance to examine early-1970s Swedish files and found radar documentation of a 1975 incident in which a military helicopter crew ordered to intercept an unknown object reported it passing just beneath them. He also described the 1980 Dämma Jaure case, in which his team says it located a sonar return from an object embedded in a lake bottom, and recounted that Betty Hill told him she had collected debris from an object that crashed near her home before the 1961 Betty and Barney Hill encounter. The program also reported that nearly every Swedish UFO photographer of the 1970s whom Svahn contacted eventually admitted faking his picture, and that the only photograph he fully trusts is a 2005 mobile-phone image he compared with military radar returns.

In Sweden, Svahn is known as much for public education as for case work: he was named Årets folkbildare, the country's adult educator of the year, in 2024, appeared that year in Felix Herngren's television series about the UFO mystery, lectures in a Linköping University course on UFOs as a research subject, and hosted a Sommar i P1 program on Sveriges Radio in 2025. His investigations and archival stewardship have made the Norrköping collection a standing resource for historians studying how UFO reports were made, investigated and preserved across Europe.