They probably sent the $3,000 deposit to someone in Nigeria via Western Union.
I read she signed a lease by fax. Some transactions should not be done online or via fax if you have never met the recipient of your money. It’s too risky. If I was about to spend $3000. for something as significant as a family home, I would want to know something about who was getting the money, and if there were any conditions that would automatically void the deal.
Making a deal like this still doesn’t explain why someone chose to smash in the back window.
The kind of person who would try buying a house in this manner may have their own things they wish to hide.