The Nigerian Counterfeit Check Fraud:

Bankrupting thousands through online and offline Classifieds

Post banks:

We have begun receiving letters from victims who have wired funds to Post banks for pick up.  Although funds must be wired to a specific account, the account is a throwaway - only opened for the purpose of receiving victim funds.  Once the transfer is made, the account - opened with false information - is immediately closed or abandoned.

Check cashing stores:

The new trend among Nigerian Counterfeit Check swindlers is to ask or instruct the victim to go to a check cashing store, cash the check, and then wire the requested funds to wherever by Western Union.

This makes it faster for the swindler to get his money.  If he can persuade you to do this, it means he (or she) won't have to wait for the bogus check to "clear" through the bank.  (See JoesBank)

Check cashing stores are prime targets for malicious check cashers.  They cannot and do not make the determination as to whether you are a criminal or the victim of a Counterfeit Check Fraud.  That is not their job.  They leave that to the police who will arrest you now and ask questions later in what is called a "reverse sting."

In a reverse sting the suspect is kept in the store for as long as possible, endorsing the check and providing identification, while the clerk or manager contacts the police who  arrest and handcuff the suspect on the spot.