The trope of chalk outlines around bodies was never a real thing that cops did.

It was invented by Hollywood in the 50s to suggest the presence of a corpse or murder without showing a corpse onscreen, which would have caused the show to be classified out of its desired classification or be censored.

Cops never did that because it would contaminate the scene and wasn’t actually useful to them

Spray Chalk; it’s a thing.

Dude doesn’t have a chalk roller? He’s pretty shit at his job if he doesn’t know how to use chalk on grass like a sports arena would.