Recently, a lot of bank transfer scams have been occuring in our city. ALC gives "billing fraud" and "bank transfer scam" as translations for 振り込め詐欺。　"Fraud" is an uncountable noun, which is hard to use in a sentence like this where you're talking about "many" of them, so I went with "bank transfer scam" because it's countable. "Now" isn't really correct as a translation for 現在 - it just doesn't work that way. "Recently" I think is your best option; it has the same meaning and tone as 現在。"Lately" is another option, though slightly less formal. I changed "happen" to "occur" to make the sentence a little more formal, which matches the Japanese. And, because you're talking about events that started taking place recently and have continued until the present, you have to say "have been (verb)ing".

Billing fraud is where a criminal pretends Using "means" this way is close to correct, but technically just a little "off". The use of "where" to express this idea is very common in conversation - not so much in writing, but I think it works well here. It's a good 言い方 to know ;)

identification number and withdraw money from his or her account. I'm not sure why, but making the end of the sentence longer sounds a bit better somehow. It "flows" a bit better. Also, "withdraw" sounds a bit better if it's part of the "...to withdraw money from his or her account" conjunction. That's why it's "withdraw" instead of "withdraws". The way you wrote it wasn't wrong, however.

Of course, the criminals are very bad.

However, victims who blindly believe what strangers tell them are guilty, as well. You're better off using words like "wrong" and "guilty" for 悪い here. "Guilty" is definitely better here, and I would probably recommend "wrong" for the 犯人が悪い sentence. Aside from that, I added "what strangers tell them" because "blindly believe strangers" was too short, and sounded a little weird.