The figures were released Wednesday, just two days after Officer Peter Figoski was shot and killed in the line of duty with an illegal gun.
With the emotions from the shooting of Officer Figoski still raw, the Mayor launched a new front on his battle against illegal guns, this one on the internet.
"How about the Smith 9mm. You take $425 for it?" the private investigator asked the gun seller.
Private investigators working for the city contacted 125 private online gun sellers.
More than half agreed to sell their firearms even after being told by the undercover investigator he could not pass a background check.
Seller: "No background check, no nothing. No."
Investigator: "Good, cause I probably couldn't pass one."
Seller: "Really? Don't say that, man (laughs) I don't want to hear that."
Two days later, they meet to exchange money for the gun.
Seller: "All right, sir. One, two, three, four, fifty."
Investigator: "Well listen I appreciate it."
That's how the undercover investigators bought all these guns: quickly and anonymously, including a 9mm Ruger, the exact make and model as the gun used to kill Police Officer Peter Figoski on Monday.
The Mayor defended the undercover sting in Ohio and the city's spending of $300,000.
"If I had to spend double that money to save one police officer's life I would do it instantly. We obeyed the law in Ohio, we obeyed the federal laws," Mayor Bloomberg said.
Eyewitness News first exposed the threat posed by anonymous, private gun sales on the internet.
Eyewitness News legally purchased a semi-automatic assault rifle, with 200 rounds of ammunition without ever showing any ID or undergoing a background check.
Nine years later, the city's internet sting shows how the number of gun websites has grown, at least 4,000, many private dealers selling to anyone.
"1-95 is a very effective way of getting guns into the city, we don't need an electronic highway to make it easier," NYPD Commissioner Ray Kelly said.
Investigator: "Can I take a look?"
Seller: "To right ahead feel free."
The Mayor says he's not opposed to gun ownership, but believes that all gun purchases should require a background check and only Congress can make that happen.
"You damn well better do something, we are not going to have more Peter Figoski's, and if they do, shame on everybody that could stop this," Mayor Bloomberg said.
Despite several attempts, the National Rifle Association declined to comment.
Meanwhile, the mayor says websites that sell firearms should require users to register first which he believes would deter criminals.
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