I've found this sentence in a Straightforward intermediate student's book (p7):
"I never miss." Mitty is holding a heavy automatic and the crowd believe him
Shouldn't it be like 'the crowd believes him' ?
"Crowd" is being used as a plural in your example.
Collective Nouns (group, jury, crowd, team, etc.) may be singular or plural, depending on meaning. In your example it is being used as a plural. (Source)
Here is an illustration for your understanding. Hope it helps:
From Oxford learners' dictionaries:
crowd: [countable + singular or plural verb] a large number of people gathered together in a public place, for example in the streets or at a sports game
The crowd was/were shouting and cheering.
Note: This is an AmE perspective (BrE is different, see comments/other answers)
Crowd is singular. Crowds is plural. You can't use crowd plurally, you have to use crowds if you mean more than one crowd.
Verbs work the opposite of nouns, verbs that end in s or es are singular third person and verbs that don't are plural third person. (Anything not third person uses the form without the s or es).
So it's always crowd believes and crowds believe.
Nouns that describe a group of X as a whole are singluar, if they refer to one of that group. If there are multiple groups of X, then plural is used.
I don't know where the pile of papers is (pile is singular because it refers to one group of paper)
I don't know where the piles of papers are (there are two or more stacks of paper)
I think it's technically wrong, but you might hear something like this where a plural pronoun is used. I'm not sure whether referring to a virtual "all of the papers" which can be argued to be implied is totally wrong here.
I took that pile of papers and threw them in the trash.
Interesting that the English (the individuals who live in England) in common usage always consider a "crowd", "team" or "mob" to be plural.
"Manchester United have finally signed what they have been missing"