central Minnesota authorities discovered human remains in a car submerged in the Mississippi River, after the car turned up on a fisherman's sonar

The sheriff's office contacted a tow company to help remove the car, which the Sartell Police Department said was "intact but severely deteriorated, had been underwater for decades and was filled with river sediment." 

The sheriff's office says the car was a 1960s-era Buick, belonging to Roy Benn.  Benn was last seen in Sartell on Sept. 24, 1967, driving a blue 1963 Buick Electra. He allegedly had been carrying a "large sum of money" when he was last seen

Benn, a widower who owned an apartment building and an appliance service business in nearby St. Cloud, was considered financially comfortable and known to carry substantial sums of cash. Authorities at the time said he may have been carrying thousands of dollars when he vanished, according to the outlets.

Benn, who was 59 when he went missing, was declared dead in 1975. However, the case remains unsolved.

https://www.cbsnews.com/minnesota/news/sartell-car-found-river-missing-man-roy-benn-cold-case/

https://www.cbsnews.com/minnesota/news/sartell-car-found-fisherman-crack-in-cold-case

https://people.com/remains-found-in-river-may-solve-minn-cold-case-11791274