Documentary is used with these nouns:
evidence, film, photograph, photographer, photography, programme, proof, record, series, source, video

film, radio, television, TV
controversial
science, wildlife, etc.
forty-minute, half-hour, hour-long, etc.
feature (esp. AmE), feature-length
fly-on-the-wall (esp. BrE)

do, make, produce
She has made a television documentary on poverty in our cities.

film
air (esp. AmE), broadcast (esp. BrE), show
see, watch

feature, film, programme/program, series
a documentary film maker

in a/the documentary
There were some interesting interviews in the documentary.

documentary about, documentary on
a documentary about identical twins