They are the source of intrigue in countless books, movies and tv series.
The official name is confidential informant.
But long-time cops say one word is used more often in jails, prisons and on the street.
Members of undercover drug teams say snitches are a valuable resource when it comes to busting big time drug dealers.
And top commanders say, snitches are helping police win the decades long war on drugs.
Jeff Wilson runs the West Central Drug Task Force.
And he says big busts wouldn't be possible, without the use of confidential informants.
"They're our bread and butter. Our intelligence base comes from people we interview", Wilson says.
Wilson says at any one time, multiple confidential informants will be quietly gathering information on drug dealers and suppliers.
He says the vast majority of the drugs in this area, are brought in from the Twin Cities, Chicago and Milwaukee.
Top police commanders in Eau Claire say without snitches, those drug dealers would operate in secret.
"It's critical. There are many times when we're not able to solve a case without confidential informants", Deputy Chief Eric Larsen says.
So where do the confidential informants come from?
Wilson and Larsen say many pick up the phone when they're behind bars, and need help with the district attorney's office.
"Sometimes they have gotten themselves into legal trouble, and they're looking for consideration", Larsen added.
The task force also pays informants for help, but Wilson says it isn't much.
Sometimes it only amounts to a tank gas or a sack of groceries for a completed drug buy.
And then there's the danger of double crossing someone who's dealing.
"There's always a chance for something to go wrong, and these people know there's a chance for something to go wrong", Wilson says.
"You can never say nothing bad will ever happen. It could.", Larsen says.
But both say they've been fortunate over the years, and have never had a snitch get hurt.
While the danger is there, the cops who run drug stings say without people willing to get involved, their job would be much tougher.
"The information they provide to us, is invaluable as far as getting into tighter knit circles, where an undercover officer or traditional police officer cannot get. If you don't have good informants, you don't have good information. You're only as good as the information you receive and what you do with it", Wilson said.
He says he's had a number of people serve as confidential informants who were not in trouble with the law, but instead, were worried about a family member's drug habit.
He says any ordinary person can be an informant, just by picking up the phone and calling his office of your local police department when you see something suspicious.
He says some of the biggest cases he's worked on started out, with a phone call from a concerned person, and ended with people going to federal prison for running multi-state drug trafficking operations.