Example with a context (news article: Russian police arrest three after dramatic Moscow shootout):
In their last crime, the alleged robbers had grabbed more than 8 million rubles ($146,000) in an attack on a cash courier in May, police said.
What's wrong with saying the police said? What's the nuance? Check that article. Almost every time they use the word police, there's no article in front of it.
Best Answer
There is nothing wrong with saying "the police." Here is just two articles from the New York Times, a newspaper that seems to prefer "the police":
Bikers Jailed After Waco Shootout Deride High Bonds and Slow Justice
New York Police Detective Shoots Gunman Who Wounded Man
Notice also "the authorities." The article also has "officials." So the NYT's use of the definite article with such terms is varied. If you check other articles in other newspapers or news sources you will routinely see "authorities" and "officials" along with "police" as having said something. (The) police is considered plural, so it fits right in there with the two plural words. In fact, sometimes (the) "authorities" are (the) "police."
There is little difference in meaning in this context whether one makes a definite reference (using the) or an indefinite reference (not using the). As far as journalism goes, it is a stylistic choice.
The article Police or the police? that Collin links to is pretty good. But it doesn't really say anything surprising.
Writers often use the zero-article with plural nouns when they want to make an indefinite reference. This indefinite reference can include being indefinite as to the number of, say, units involved, whether police or bullets or ants.
is indefinite. We don't know how many and the author doesn't really care to tells us.
Same thing.
However, if "the" is used, it can refer to "the police department."
refers to calling the police department, or the police force. This is the same as when we say
But sometimes it is pretty hard to distinguish. If you are at the scene of a crime or accident and two police officers pull up in a police car, and you say the police are here, it's hard to believe that you are not referring to the two officers at the scene--at least as representating "the police department." Which is fine. We say the same when the firetruck pulls up with 5 firefighters: the fire department is here.
Other newspapers seem to be going away from using even the standard "call the police":
Manhunt focuses on prison area; Philly tip discredited (USA Today)
I'm just highlighting the phrase call police because USA Today seems to prefer this over the normal, everyday phrase call the police. For many, this use of police without the the will seem strange (see Ngram below). And that is not all: analysis of Police or the police? falls apart. Because we don't call an "indeterminate number of police officers" when we "call (the) police," we call "the police department." And I won't be yelling "call police" any time soon. (And hopefully not "call the police" either.)
The conclusion, therefore, is that this is more of a style issue than a purely grammatical issue.