Weissner is a character appearing in both the novel Where Eagles Dare and its movie adaptation.
Oberst Weissner was a brutal German officer who served as the Schloss Adler's chief of security. He was sent to arrest John Smith's team under the pretense that they were German deserters. He found them in the Zum Wilden Hirsch. The owner, Josef Wartmann, thought that Weissner had come for him, but the Oberst reassured him. Barmaid Heidi Schmidt, who Weissner knew fondly, pointed out Smith and the others to the Oberst, who arrested them. He sent Olaf Christiansen, Lee Thomas and Edward Carraciola away for interrogation with his men, while he personally escorted Smith and Morris Schaffer in his Mercedes staff car.
En route, Smith pretended to be Heinrich Himmler's nephew and demanded to be released. A terrified Weissner believed him and complied. He and Schaffer commandeered Weissner's Mercedes, forcing him and his men to get out, and drove off, leaving them on the side of the road. Realizing he'd been tricked, Weissner pursued in another car. Smith and Schaffer faked their deaths by pushing the Mercedes off a cliff into the Blau See, and Smith threw his hat in the water. They hid, and when Weissner and his men found the floating hat, they believed the two impostors were dead.
Later, he and his men attempted to intercept the cable car carrying Smith, Schaffer, Mary Ellison and Cartwright Jones by waiting at the bottom. However, they planted bombs aboard and then they leaped out into the Blau See. Weissner didn't see them jump and the empty cable car blew up before reaching the control room.
Weissner is an SS standartenführer and his fate is much different in the film than in the novel. Whilst driving in the car, Smith grabs the gun of one of the soldiers riding in the backseat with him and shoots the driver. The car crashes, flinging Weissner through the windshield and killing him.