I have made a bad mistake/judgment with a person internationally and when I canceled the transaction he threatened me. I live in the US and this person lives in Europe. I am scared they will come after me somehow because they were really counting on a lot of money. How can I handle this.

So what type of contract was it ? Was it in writing ?

If you violate the terms of the contract they may sue you for funds you owe them

No there was no contract.

And, more info??

No, it was a deal through email only. I just need to know if I might need a lawyer.

Did you take the email threatening you to the Police?

Sorry, it sounds somewhat like a scam perhaps going on? The lack of giving info sounds like it was something that perhaps was not 100 percent honest.