From the article:

When the vehicle was pulled from the water, skeletal remains were found inside. One week later the remains were positively identified as belonging to Mr Moldt.

Decomposing is typically only in reference to tissues/organs/soft matter. Things that bacteria, insects, and animals can eat (thus causing the decomposition). This happens rather quickly.

Bone can't be eaten, so when all that is left is the Skeleton there is no more decoposing. As long as they aren't crushed or destroyed through other means, bones will last virtually forever.

I assume he was identified by dental records or something similar (healed broken bones, etc).

> Bone can't be eaten

Squirrels eat bones. Skeletons disappear rapidly in the wild.

Neither the squirrels nor the bone-eating fish were able to get through the car doors.

TIL. Thanks squirrels for keeping our parks/woods/neighborhodos free of dead animal carcasses :)

> bones will last virtually forever

Ironically, like plastic. :)