My scammer now warns me not to accept funds. Why?

I have rental property online. My scammer wanted the property for certain dates. I sent him a lease with the address left out because at the time I was not completely sure he was legit. He called me on my cell phone and had good English-said he was from Nigeria. I told him not to call me, and to email if he had any questions. He emailed me today that he was robbed and his passport and cell phone were stolen and for me not to accept any checks that may be mailed to me. Why is he warning me not to accept any checks from someone posing as him? (I am going to email him back and tell him the house is not available, that a group of New York City police officers have rented it now.)

Hi Angel and welcome.

It appears the scammer is grooming you to gain your trust, or is concerned that another scammer is also talking to you. Scammers usually work in groups and he may be concerned someone is trying to "steal his job"

Any check he sends you, will be for more than the required amount. You will be asked to send the overage to yet another scammer, "The person furnishing the property". The bank may clear the check, you send the money to the scammer and when the bank discovers the fraud, you will be responsible for repaying them.

Your idea is good. Tell him the property is no longer available.