after 49 years in a lake with the front in the mud, the elements (lack of oxygen in the mud) caused a strange contrast with the rest of the Vauxhall that rusted

https://tywkiwdbi.blogspot.com/2021/11/anaerobic-preservation-exemplified.html via https://www.tv2.no/nyheter/14376554/

One night at dinner with his wife, William Lie got up in the middle of the meal, and drove off. 

Ten days after the last time he was seen alive, the police linked his disappearance to the discovery of camping gear belonging to a missing man, abandoned by the mountain lake Trytetjern near Nesbyen, only 150 meters from where he was last seen.

 Among the items was a travel radio with a sticker indicating that the radio had been sold in Oslo. When the police officer contacted the store, they could see in the file that the radio with this serial number had been sold to William Anker Lie.

49 years later Norway police found the answer to the disappearance, a car, using sonar and underwater drone (ROV), at a depth of ten meters in Trytetjern lake

Human remains were inside the Vauxhall, as was a letter of resignation was also found, a farewell letter and books. Some of this material was wrapped in plastic

For a good write up of the days leading to William Lie's disappearance, see https://www.world-today-news.com/in-the-middle-of-the-dinner-william-62-got-up-and-left/