what is the difference between a "deverbal noun" and a "verbal noun" please [closed]

I am currently working on -ing nominalizations and I've noticed that some grammar books refer to verbal nouns as deverbal nouns. Do you (English native speakers) make the difference or do you consider these two types of nouns as being the same ? The only thing I'm sure of is that both verbal nouns and deverbal nouns derive from verbs. I just want to be sure that these two concepts exist in English and that a difference exists. Thank you, because I'm starting losing my mind!!

A verbal noun, for example a gerund, is grammatically used as a noun but is still quite verb-y.

Shooting clay pigeons is a pleasant activity.

vs.

A deverbal noun, which is fully nominalized as a common noun and can take plurals, determiners, etc.

The police apprehended the people who carried out the shootings.

Note that since a verbal noun and a deverbal noun can sometimes have identical forms, this might be a bit confusing, I suppose. But deverbals don't all end in "-ing" or "-ed", for example.

(Mnemonically, you can think of "verbal nouns" as being verbal in nature, while "deverbal nouns" are nouns that have been de-verbed.)